The Thesis as a Window into Dennis’ World

In December 1967, Dennis had nearly completed his doctoral thesis, which weighed in at nearly 180 pages of dense mathematical expressions and symbols. In January 1968, he sent out two identical copies of the document to two close associates, initial faculty advisor (by then gone from Harvard for several years) Patrick Fischer, and grad school colleague Albert Meyer. This late draft still needed more than 50 simple typing corrections spread over 30 pages. On the Fischer copy title page, Dennis wrote the names of his four faculty advisors.

The following month, February 1968, Dennis had produced a new, near complete draft, correcting all typos from the January draft.  A small note taped to the cover page listed six minor still-to-be-made corrections.  This near-final draft, its first few pages now disfigured, was found by David Brock in Dennis’ personal archives after the family donated his papers to the Computer History Museum.

Fischer Copy - Cover Page

On February 7, 1968, Bell Labs wrote to Harvard asking:

“…Would you please verify for our information that Dennis M. Ritchie will receive his Doctor of Philosophy degree in Mathematics in February 1968. Thank you very much.”
To which Harvard replied on February 20th:
“With reference to your inquiry of February 7, 1968, this is to inform you that Mr. Dennis M. Ritchie is not a candidate for his Doctor of Philosophy degree in February 1968.

So by February 20, 1968, it appears that Dennis was no longer on his PhD track. There are two rumors about how the thesis came to be derailed. Each of these was recorded in interview transcripts with David Brock.

Albert Meyer
John and Bill Ritchie
Lynn Ritchie


The first comes from Albert Meyer who in 2018 related the story told to him by Pat Fischer:

“As Pat tells the story, Dennis had submitted his thesis. It had been approved by his thesis committee, he had a typed manuscript of the thesis that he was ready to submit when he heard that the library wanted him to have it bound, and give to them. And the binding fee was something noticeable at the time. I forget whether it was, you know, $50, $250, something or other. But it was a– not an impossible, but a non-trivial sum. And as Pat said, Dennis’ attitude was, “If the Harvard Library wants a bound copy for them to keep, they should pay for the book, because I’m not going to!” And apparently, he didn’t give on that. And as a result, never got a Ph.D. So he was more than everything but thesis. He was everything but bound copy.”

The second rumor comes from sister Lynn. In her 2018 interview with David Brock, she says: 

“There was something about how he had already got the job at Bell Labs and he had gone over the three years somehow, the allocated time, by just a few months, I think. And when he came to submit it he discovered that he was going to have to pay like an extra year’s fees.  And he just thought, “That’s ridiculous,” you know. 
“Brother John feels that there was something else going on with Dennis Ritchie’s actions beyond a fit of pique about fees: He already had a coveted job as a researcher at Bell Labs, and ‘never really loved taking care of the details of living.’”
These stories basically match up, it makes sense that Dennis could have had an administrative fee-based flare-up that stopped his thesis in its tracks.  Why not? This is as good an explanation as any for what might have happened.
Whatever the cause, the effect was that Dennis put his thesis copy on the shelf and never made reference to it again. Apparently then nobody ever read the dissertation during his lifetime.  
But it turns out that there is another story here that is kind of bigger once it is focused on. If Dennis didn’t get a doctorate then he technically wasn’t a doctor. And the question, “Do you in fact have a PhD or not?”, would have remained live and relevant for Dennis across his lifetime, increasingly so as the major award ceremonies kept piling in.  
So what do we know about what actually happened, how this question played out in specific situations?  Here is our best list of references (so far) for Dennis’ doctoral status from years 1982 to 2011:

 In 1982, Electronics Magazine presented Dennis and Ken their annual Award for Achievement. The accompanying article accurately reports that “Ritchie joined the labs in 1967 after eight years in which he ‘almost’ attained a doctorate from Harvard.”

 In 1983, when Dennis and Ken won the Turing Award, the official Dennis biography on the website stated that “Ritchie received a BS degree in Physics in 1963 and a PhD in Applied Mathematics in 1967 from Harvard University.”

– In 1991, a Unix World article, “Who Is The Real Dennis Ritchie”… inaccurately states “He holds three degrees from Harvard: A Ph.D. in applied mathematics, an M.S. in applied mathematics, and a B.S. in physics.”

 Dennis and Ken won the National Medal of Technology in 1998. The “Dennis Ritchie Laureate” biography page on their website is silent about his education status, does not call him either “Dr.” or “Mr.”

 A 2004 Economist article, “Unix’s founding fathers”, refers to Dennis as “Dr. Ritchie”, does not reference his educational background.

 The Japan Prize (2011) webpage says that Dennis earned a “Ph.D. in Computer Science, Harvard University”, in 1968.

 Wikipedia references to Dennis’ education status generally convey that he has a PhD though are confused. The Dennis Ritchie Wikipedia page lists “Alma Mater:  Harvard University (Ph.D., 1968).” The article text says “He graduated from Harvard University with degrees in physics and applied mathematics(8)”. Footnote 8 then opens to a Wall Street Journal obituary that says Dennis “majored in physics at Harvard University and then earned a doctorate there in applied mathematics”. But, he is referred to as “Mr. Ritchie” throughout the obituary, without reference to why.

– Further confusion comes from the Computer History Museum. David Brock broke the story that Dennis never received his doctorate. And yet, the Dennis Ritchie profile page on the CHM website (October 2021) states:

Dennis Ritchie was born in Bronxville, New York, in 1941. He graduated from Harvard University with degrees in physics and applied mathematics and with a PhD in mathematics (1968).”
 In 1998, Dennis recorded an interview with Princeton professor Michael Sean Mahoney, as part of a larger project on the history of UNIX. The interview was wide ranging, lots of probing questions and detailed stories about the early days of grad school and early Bell Labs. The entire interview is great and worth reading. We have highlighted the “Grad school experience” questions and answers here. This part of the interview would have been a perfect opportunity for Mahoney to come out and directly ask Dennis, “So am I right that there is some story about your doctoral thesis?” But instead, you can see for yourself how Dennis is able to direct the conversation away from the topic without discussing his thesis or actual degree status.

 And what about Dennis’ own description of his educational achievements from his Bell Labs biography page?

I was born Sept. 9, 1941 in Bronxville, N.Y., and received Bachelor’s and advanced degrees from Harvard University, where as an undergraduate I concentrated in Physics and as a graduate student in Applied Mathematics. The subject of my 1968 doctoral thesis was subrecursive hierarchies of functions.”
Based on this, what do you conclude about Dennis’ doctoral status? This is a masterful use of nuance right here. Dennis rarely if ever talked with anyone about his thesis experience during his lifetime. He did have one conversation with sister Lynn. She told David Brock in 2018:
Late in life Dennis said, “Well, you know, I never actually got the piece of paper.” And we, I mean, it wasn’t an amazing surprise, but..  And he began to talk about it a little bit… I think he made some reference to, “Oh, it was just, you know, there was a lot of hassle involved, a lot of red tape.” And this would really, literally, only have been a few years before he died, I think.
All memory of the thesis and questions coming from it could well have died when Dennis passed in October 2011, except for one last tribute. In Spring 2012, Mauricio Cortes from Bell Labs wrote to the dmr sibs. The Labs was organizing a tribute to Dennis, “The Lasting Legacy of Dennis Ritchie”, for September 7th, and Cortes was preparing a document that would contain everything that Dennis had ever written. The project was going well except that he was having trouble finding a copy of Dennis’ doctoral thesis. Could we help?


Tribute Poster from Mauricio Cortes
Mauricio’s email

It turned out that Lynn was able to help. She contacted Fischer’s widow Charlotte who still possessed Pat Fischer’s draft, which she retrieved and sent to Lynn who was then able to present the dissertation to Mauricio from the Dennis Day celebration stage. (We have since donated all of Dennis’ papers to the Computer History Museum.)

So the dmr thesis was found! And the story has continued to unfold…

In June 2020, David Brock published “Discovering Dennis Ritchie’s Lost Dissertation” on the Computer History Museum website. He describes what the thesis was actually about and why it was important, then tells the Albert Meyer library fee version of the kill story.

In Summer 2020, David Brailsford, University of Nottingham professor emeritas, working with Brian Kernighan and Chuck Bigelow, began the process of fully digitizing the entire dmr dissertation. Brailsford describes this project and what it entails, in a May 2021 video blog post on computerphile. Bill Ritchie signed onto this effort and has been working on dmr thesis typography where he is finding even more new revelations. (See Anatomy of a Thesis section).

And now a new question is emerging: How was Dennis able to obfuscate his degree status in this way for so long, his entire lifetime and even through his obituaries? 

What do we make of the fact that no one – not the Turing Award committee, not the National Academy of Engineers, not the Japan Prize organization – seemed to know the exact status of Dennis’ educational achievements, they didn’t know that he was not in fact Doctor Ritchie. Nobody seemed to know, nobody talked about it, everybody let Dennis pass through his entire professional life without ever having to confront or explain himself. How could that be?

In his adult years Dennis had a reputation for being famously private. This is best captured in the 1991 UNIX World article“Who is the Real Dennis Ritchie?”.

There were topics that were completely off limits with Dennis – mostly having to do with any form of personal intimacy. This was true for his Bell Labs colleagues, who speak of Dennis’ personal life as a kind of private zone where they do not tread, and true with his siblings also. This was just his way.  
As an adult, Dennis lived an ascetic lifestyle. In September 1967, he moved back into the attic of his family home and set up a home office in the basement, where he lived with his parents until 1989.  He worked from 1PM until 3AM six days a week, Sundays off for reading. He had no friends outside of his business colleagues, he rarely socialized, he did not have (nor never had) a relationship with anyone, he wouldn’t talk about/acknowledge discussion about emotional issues in any form.  (He did have a wonderful family who loved him dearly and whom he loved dearly as well.) It was almost as if he needed to blot out any awareness of his personal life from the world by using the strategy of having no personal life to be observed.  
This affect wasn’t just something neutral, it could be an active force.  
Here are Lynn and Bill Ritchie discussing this aspect of Dennis’ personality in their Computer History Museum interviews with David Brock:   

L. Ritchie: In high school and college, Dennis hadn’t withdrawn in the way he sort of did later. And when I say “withdrawn” I mean, and again, I think that if you wanted to talk to him about something, he was very capable of putting up a complete brick wall. And you always knew it. I mean, there was just no– you couldn’t get through to that if he wasn’t in the mood to. A lot of body language. I mean, a lot of the times you would just know by the body language not to even try.” 

B. Ritchie: …and Dennis, he would just, — John used the term force field. You know, Dennis had this ability, you put up the force field and then you didn’t even — it was like otherworldly how he just — you were not—”


The siblings often talked about this quality that Dennis had, the shake of his hands, the exaggerated eye rolls, when he was deflecting you from a personal topic.  Even now when we try to solicit Dennis gossip from his BTL colleagues, they are uncomfortable with the topic and don’t much want to talk about it… but this feels like the dmr force field is present with them still. It is a real experience.

What we hadn’t considered before is that Dennis could have or would have used his force field techniques to obfuscate to the world about his doctoral status!  It certainly stands to reason… for his entire life he was shading the record here which was very uncharacteristic of him, there must be some explanation for how that could have happened and how nobody ever made a question out of it.

It’s funny… Steve Jobs, who died 6 days before Dennis in October 2011, was famous for having a Reality Distortion Field. Is it possible that Dennis had an inverse and opposite field to this, a Deflection Force Field, that he used to obfuscate all talk of doctorateship?  What else might he have been doing with this power?   

By definition the dmr force field was invisible, that’s one of its powers.  You wouldn’t focus on it, you would focus away from it. But what else explains the life-long disclarity and confusion and lack of resolution around the topic of whether Dennis had a PhD and was formally a Doctor? We have some more interviewing to do, stay tuned.

Next up is to ask the question, “Was Dennis always like this?”.  Meaning, was he always a brilliant anti-social loner? And it turns out that the unequivocal answer is, “No he was not.”

The Brock interview with Lynn took place in Summer 2018, just months before her death. Brock had previously interviewed John and Bill together.

Lynn Ritchie

Lynn does a great job to address this question in her interview.  Here we have excerpted highlight paragraphs from the transcript, patching together copy blocks that focus specifically addressing Dennis as a youth, Lynn speaking in her own voice paragraphs rearranged to better tell a narrative story.

Brock: And your impressions of Dennis as a young man, you know, maybe through his undergraduate years… “ 

L. Ritchie: I think Dennis was just was a very unique person. The instinct maybe is to want to slot people into some hole that says they’re introvert or extrovert or this or that. And I think– but what led to him being like that because really of the rest of us– maybe the reason the rest of us haven’t done what he’s done is because we’re not like that. I mean part of it does feel that– but it’s the chicken and egg thing. Who knows? And it certainly is the case that we weren’t brought up to express real deep emotions or difficult emotions or even recognize them. And, again, I think the rest of us have kind of coped with that in our own way. And realized probably to get on with our nearest and dearest you do need to face up to a lot of these things. And whether the fact that Dennis didn’t have a life partner meant that he didn’t need to do. I don’t know. It’s interesting. I feel quite defensive about Dennis. I think he was a very unique human being with really wonderful human characteristics and whether you can call it shyness. I don’t think it was really was– it’s not shy. Just privacy. Yeah. 

Dennis was never interested in just doing things for show or to fit in with conventional things from being a little kid. So he always was sort of on his own path. But willing to– not imposing that on anybody else or, I think understanding other people who weren’t doing it that way he was. I mean, we were, because we were only two years apart, we did do a lot of playing together. And he was I guess it was starting later than that when we got into maybe junior high or high school, but that he was a real pal. And there was one of my closest friends still, who is from Summit who now lives in Washington, but we often talk about how that we would bug Dennis when he was driving and we were like 16 or whatever, to take us out. Every Sunday we would, he’d take us out to a parking lot and we’d– And, you know, he was really sweet about it and did it, but it did take us nagging him.”

Brock: What was your impression of how your brother fit into the middle school and the high school and how did that compare to — was that similar to the way that you were fitting in both academically and socially and in terms of extracurriculars?”

L. Ritchie: He was always very bright. I mean, I can remember the stage when we were still in just elementary school, you know, with arithmetic and he would be doing things and I would think, there’s no way I could ever do this, whether it was multiplication or, you know, whatever. And then that wonderful feeling when you can do it. 

But he, he was always– I mean, I can remember, to my shame, really, feeling that I wish Dennis was more like the “All American Boy.” I mean, he was never athletic. And he was a little bit goofy and nerdy. But, you know, really the sweetest person on Earth. And as I said, I can remember thinking in that period of one’s life where you want everything to be whether it’s super conventional, “Oh, I wish he were more like the high school quarterback,” or something like that. But it never, you know, he just wasn’t, and he wasn’t ever going to be. 

So I think I followed much more of a conventional path. I was certainly in elementary school, I don’t think there was that much difference, but once I got to junior high, I was applying or, you know, running to be class vice president or whatever. Although our extracurricular activities were sort of similar. We both were in, like, Latin Club and although Dennis would have been in a lot of the science clubs. So let me think. I mean, he was always– He was always somebody who was certainly on many notches ahead of me, even though I was doing very well at school, but, you know, it wasn’t really comparable to Dennis. He just was much more imaginative, I think, and yeah.”

Brock: Do you think, did he have a circle of friends?

L. Ritchie: Yeah, he did. There were a couple of friends in particular who lived nearby and again, I can remember seeing quite a lot of them. And so he did. He didn’t– I don’t– I guess he didn’t hang out with them in the same way that maybe I would have been hanging out with my friends or John or Bill. But he definitely did. I mean, it wasn’t like he was a loner by any means. 

Because again, the talk about girlfriends. And I– One thing, I might have started Dennis off on this path. He had gone to Harvard and I would have been a junior in high school, so it was our high school prom. And there was a new girl in my class who I’d gotten really friendly with who must have met Dennis already who had a big crush on Dennis. And she, I really liked her. She was very, you know– So I fixed them up for our junior prom. And of course, being the little sister, I probably overdid it.  And they went to the junior prom but then I would follow it up by nagging him about, “Have you been in touch with Kim?”  And I probably ruined any possibility of any relationship, who knows. And certainly, in the summer in the Poconos where we would all spend the summer– He, again, John and Bill did mention this. He was really very, very active and he did have summer jobs there working on the activities.  And he, every Friday night there was a square dance and there were a number of people who are still around because it’s this community where people go back for years and years.  And then when I went to college near Boston, too, and my close friends from the dorm and I would go into to Dennis– to Lowell House, where Dennis was. I think he was there the whole of the four years. And we would often sort of all get together. I don’t know, there were three or four of his roommates. You know, they had a, like, a suite.  And we would quite regularly go in there. And I know at least one of my friends certainly if Dennis had made a move, she would have too. But it was sort of a group of, I mean, it was really lovely friends and they would cook for us and things. But so it was sort of a group gathering rather–  Rather than having dates or anything like that. But I continued– So, I’m two years younger, so, like, for me, yeah, well, Dennis had gone to– was in graduate school, that’s right, the last two years of my– So I don’t think we saw quite as much of each other as once he got into graduate school because he moved. He was no longer in Lowell House. He had an apartment or something. But we still did, you know, we’d still meet up.


Lynn’s best-friend-since-grade school, Tansy Blumer, also a good friend to Dennis, corroborates Lynn’s description that Dennis was outgoing and social in his youth. In a 2012 email she recounted several Dennis stories:

“I remember several times at PLP when Dennis and I were kind of ‘together’ for a square dance or a beer party. This was notable not so much because I considered it a date, but because when you were with Dennis, there was always something interesting to be learned. He would point out the locations of stars and constellations in the sky, for instance, or he would show me where the bats had a roost and point out where they were flying. I remember being on the lake in a rowboat with him and asking timidly if the swooping sounds and breezes in my face were because of the bats. Dennis assured me that they were “robins” that were “just curious” about who was in the boat. But, of course, I know they were bats!!!! I am a bit like John with snakes when it comes to bats, and Dennis realized this and kindly decided not to tease me about them.”

“When Dennis was on The Force and lived on The Street, he got into the best shape I have ever seen him in. It was a new way of seeing him, and I often think of how he looked that summer – tan, developed muscles, etc. I doubt that he was even aware of his newly acquired musculature,  but it was interesting to see this physical side of him. He was very popular while on the Force and I think he may have won an award or two for his helpfulness and for his overall contribution to PLP.”

Tansy Blumer Full Transcript

Lynn had another memory she shared with David Brock in her interview:

“Another thing, when I was in fifth or sixth grade and Dennis had gone to the junior high, that’s the way, it was one through six in elementary school and then junior high and then senior high. And for the first, because the elementary school we had all gone to was in a part of town, there were probably eight altogether in Summit, where really it was very, very middle class. And suddenly, he was encountering kids who weren’t, you know, were black kids or Italian kids, “the hoods” as we would call them.

And we were just fascinated by his stories of the hoods. And this was in the mid- to late-fifties. And again, the same friend who we’d bug him later to take us driving, we would sort of, you know, just when he’d come home from school, get us to tell us stories about the hoods, you know. And he, so he had an interest, I mean, he was always really observant. I think that might have come through with– I think it did come through with the John and Bill interview. Even though he I think was shy in many ways, and, you know, various people have said did I think he was on the Autistic Spectrum? I really, honestly, don’t — because I think he always was very engaged with people.”

Brock: I was wondering, I had after, you know, it was such an interesting conversation that I had with your brothers and just like reflecting on what I had heard, it almost sounds– I wondered if there was, if the period of change where he became let’s just say more of a private person or an extremely private person.  Did that happen do you think when he was in– while he was at Harvard, maybe, in his graduate studies days? Or was that after?”

L. Ritchie:  “I don’t think– I think it was after.

So according to Lynn, Dennis started changing and becoming more private after grad school and moving home and starting work at Bell Labs.  This makes sense to John and Bill… Dennis kept his personal creativity up until around 1968 then it rapidly became harder to engage with him. 

Here is a description from John in his Brock interview:

J. Ritchie: We were off from college, and Lynn by then was living in England, so her trips home were sporadic, but it was like this really special thing to come back together. My impression was that Dennis sort of, having spent the rest of the year either in the basement or the attic or at Bell Labs, would kind of come out of his shell and we’d all do fun games together and funny gifts. Christmas was a great time for humorous gifts. My mother and her sister would exchange hilarious gifts and one year the gift that her sister came up with was an amazing, exact replica of the head of Richard Nixon, but it was a candle. But was just– this was in, you know, ’68, so it was like, “Well…”


As a youth Dennis was social and outgoing, then in young adulthood he transformed quite rapidly to become more private and anti-social. Hard to pin down exactly when this would have been happening… except that clues from John and Lynn’s interviews suggest perhaps sometime around February 1968 might be central.  

Do we know anything else that was happening around February 1968?  Something about a thesis unexpectedly not moving forward and subsequently getting buried for a lifetime?

This story’s not done, we’ll keep digging you’re welcome to keep checking back in.  

For those of you who are interested in more details about Dennis the young man, we’ve assembled a “Best Dennis Ritchie quotes from the Brock interviews” document. Happy reading!