"The most important thing in the kitchen is the waste paper basket and it needs to be centrally located." -- Donald Knuth
Donald Ervin Knuth () (born January 10, 1938) is a computer scientist and Professor Emeritus of the Art of Computer Programming at Stanford University.
Author of the seminal multi-volume work The Art of Computer Programming ("TAOCP"), Knuth has been called the "father" of the analysis of algorithms, contributing to the development of, and systematizing formal mathematical techniques for, the rigorous analysis of the computational complexity of algorithms, and in the process popularizing asymptotic notation.
In addition to fundamental contributions in several branches of theoretical computer science, Knuth is the creator of the TeX computer typesetting system, the related METAFONT font definition language and rendering system, and the Computer Modern family of typefaces.
A writer and scholar, Knuth created the WEB/CWEB computer programming systems designed to encourage and facilitate literate programming, and designed the MMIX instruction set architecture.
"A list is only as strong as its weakest link.""An algorithm must be seen to be believed.""Beware of bugs in the above code; I have only proved it correct, not tried it.""God is a challenge because there is no proof of his existence and therefore the search must continue.""I decry the current tendency to seek patents on algorithms. There are better ways to earn a living than to prevent other people from making use of one's contributions to computer science.""If you optimize everything, you will always be unhappy.""In fact what I would like to see is thousands of computer scientists let loose to do whatever they want. That's what really advances the field.""Let us change our traditional attitude to the construction of programs. Instead of imagining that our main task is to instruct a computer what to do, let us concentrate rather on explaining to human beings what we want a computer to do.""People think that computer science is the art of geniuses but the actual reality is the opposite, just many people doing things that build on eachother, like a wall of mini stones.""Science is what we understand well enough to explain to a computer. Art is everything else we do.""The hardest thing is to go to sleep at night, when there are so many urgent things needing to be done. A huge gap exists between what we know is possible with today's machines and what we have so far been able to finish.""The manuals we got from IBM would show examples of programs and I knew I could do a heck of a lot better than that. So I thought I might have some talent.""The most important thing in the programming language is the name. A language will not succeed without a good name. I have recently invented a very good name and now I am looking for a suitable language.""There's ways to amuse yourself while doing things and thats how I look at efficency."
Knuth was born in Milwaukee, Wisconsin, where his father owned a small printing business and taught bookkeeping at Milwaukee Lutheran High School, which he attended. He was an excellent student, earning achievement awards. He applied his intelligence in unconventional ways, winning a contest when he was in eighth grade by finding over 4,500 words that could be formed from the letters in "Ziegler's Giant Bar." The judges had only about 2,500 words on their master list. This won him a television set for his school and a candy bar for everyone in his class.
Knuth had a difficult time choosing physics over music as his major at Case Institute of Technology (now part of Case Western Reserve University). He also joined Theta Chi Fraternity. He then switched from physics to mathematics, and in 1960 he received his bachelor of science degree, simultaneously receiving his master of science degree by a special award of the faculty who considered his work outstanding. At Case, he managed the basketball team and applied his talents by constructing a formula for the value of each player. This novel approach was covered by Newsweek and by Walter Cronkite on the CBS television network. As an undergraduate at Case, Knuth was hired to write compilers for different computers.
In 1963, he earned a Ph.D. in mathematics (advisor: Marshall Hall) from the California Institute of Technology, where he became a professor and began work on The Art of Computer Programming, originally planned to be a single book, and then planned as a six, and then seven-volume series. In 1968, he published the first volume. That same year, he joined the faculty of Stanford University, having turned down a job offer from the National Security Agency (NSA).
In 1971, Knuth was the recipient of the first ACM Grace Murray Hopper Award. He has received various other awards including the Turing Award, the National Medal of Science, the John von Neumann Medal, and the Kyoto Prize. After producing the third volume of his series in 1976, he expressed such frustration with the nascent state of the then newly developed electronic publishing tools (especially those that provided input to phototypesetters) that he took time out to work on typesetting and created the TeX and METAFONT tools.
In recognition of Knuth's contributions to the field of computer science, in 1990 he was awarded the one-of-a-kind academic title of Professor of The Art of Computer Programming, which has since been revised to Professor Emeritus of The Art of Computer Programming.
In 1992 he became an associate of the French Academy of Sciences. Also that year, he retired from regular research and teaching at Stanford University in order to finish The Art of Computer Programming. In 2003 he was elected as a foreign member of the Royal Society. , the first three volumes of his series have been re-issued, and Knuth is currently working on volume four, excerpts of which are released periodically on his website. Meanwhile, Knuth gives informal lectures a few times a year at Stanford University, which he calls Computer Musings. He is also a visiting professor at the Oxford University Computing Laboratory in the United Kingdom.
In addition to his writings on computer science, Knuth, a Lutheran, is also the author of 3:16 Bible Texts Illuminated, in which he examines the Bible by a process of systematic sampling, namely an analysis of chapter 3, verse 16 of each book. Each verse is accompanied by a rendering in calligraphic art, contributed by a group of calligraphers under the leadership of Hermann Zapf.
He is also the author of Surreal Numbers, a mathematical novelette on John Conway's set theory construction of an alternate system of numbers. Instead of simply explaining the subject, the book seeks to show the development of the mathematics. Knuth wanted the book to prepare students for doing original, creative research.
On January 1, 1990, Knuth announced to his colleagues that he would no longer have an e-mail address, so that he might concentrate on his work.
In 2006, Knuth was diagnosed with prostate cancer. He underwent surgery in December that year and started "a little bit of radiation therapy [...] as a precaution but the prognosis looks pretty good," as he reported in his video autobiography.
Knuth was elected as a Fellow (first class of Fellows) of the Society for Industrial and Applied Mathematics in 2009 for his outstanding contributions to mathematics. He is a member of the Norwegian Academy of Science and Letters.
He used to pay a finder’s fee of $2.56 for any typographical errors or mistakes discovered in his books, because "256 pennies is one hexadecimal dollar", and $0.32 for "valuable suggestions". (His bounty for errata in 3:16 Bible Texts Illuminated, is, however, $3.16). According to an article in the Massachusetts Institute of Technology's Technology Review, these Knuth reward checks are "among computerdom's most prized trophies". Knuth had to stop sending real checks in 2008 due to bank fraud, and instead now gives each error finder a "certificate of deposit" from a publicly listed balance in his fictitious "Bank of San Serriffe".
Version numbers of his TeX software approach the number ?, in that versions increment in the style 3, 3.1, 3.14. 3.141, and so on. Similarly, version numbers of Metafont approach the base of the natural logarithm, e.
He once warned a correspondent, "Beware of bugs in the above code; I have only proved it correct, not tried it."
All appendices in the Computers and Typesetting series have titles that begin with the letter identifying the appendix.
TAOCP volume 3 (First Edition) has the index entry "Royalties, use of, 405". Page 405 has no explicit mention of royalties, but however does contain a diagram of an "organ-pipe arrangement" in Figure 2. Apparently the purchase of the pipe organ in his home was financed by royalties from TAOCP. (In the second edition of the work, the relevant page is 407.)
The preface of Concrete Mathematics includes the following anecdote: "When Knuth taught Concrete Mathematics at Stanford for the first time, he explained the somewhat strange title by saying that it was his attempt to teach a math course that was hard instead of soft. He announced that, contrary to the expectations of some of his colleagues, he was not going to teach the Theory of Aggregates, not Stone's Embedding Theorem, nor even the Stone—?ech compactification theorem. (Several students from the civil engineering department got up and quietly left the room.)" (Concrete and aggregates are important topics in civil engineering.)
Knuth published his first "scientific" article in a school magazine in 1957 under the title "Potrzebie System of Weights and Measures." In it, he defined the fundamental unit of length as the thickness of MAD magazine #26, and named the fundamental unit of force "whatmeworry." MAD magazine bought the article and published it in the #33, June 1957 issue.
Knuth's first "mathematical" article was a short paper submitted to a "science talent search" contest for high-school seniors in 1955, and published in 1960, in which he discussed number systems where the radix was negative. He further generalized this to number systems where the radix was a complex number. In particular, he defined the quater-imaginary base system, which uses the imaginary number 2i as the base, having the unusual feature that every complex number can be represented with the digits 0, 1, 2, and 3, without a sign.
Knuth's article about the computational complexity of songs, "The Complexity of Songs", was reprinted twice in computer science journals.
To demonstrate the concept, Knuth intentionally referred "Circular definition" and "Definition, circular" to each other in the index of The Art of Computer Programming Vol. 1.
At the TUG 2010 Conference, Knuth announced an XML-based successor to TeX, titled "iTeX" (, with a cow bell ringing), which would support features such as arbitrarily scaled irrational units, 3D printing, animation, and stereographic sound.
Volume 4, Fascicle 2: Generating All Tuples and Permutations, 2005. ISBN 0-201-85393-0
Volume 4, Fascicle 3: Generating All Combinations and Partitions, 2005. ISBN 0-201-85394-9
Volume 4, Fascicle 4: Generating All Trees...History of Combinatorial Generation, 2006. ISBN 0-321-33570-8
Donald E. Knuth, Computers & Typesetting :
Volume A, The TeXbook (Reading, Massachusetts: Addison-Wesley, 1984), x+483pp. ISBN 0-201-13447-0
Volume B, TeX: The Program (Reading, Massachusetts: Addison-Wesley, 1986), xviii+600pp. ISBN 0-201-13437-3
Volume C, The METAFONTbook (Reading, Massachusetts: Addison-Wesley, 1986), xii+361pp. ISBN 0-201-13445-4
Volume D, METAFONT: The Program (Reading, Massachusetts: Addison-Wesley, 1986), xviii+566pp. ISBN 0-201-13438-1
Volume E, Computer Modern Typefaces (Reading, Massachusetts: Addison-Wesley, 1986), xvi+588pp.
Selected papers series:
Donald E. Knuth, Literate Programming (Center for the Study of Language and Information ... Lecture Notes), 1992. ISBN 0-937073-80-6
Donald E. Knuth, Selected Papers on Computer Science (Stanford, California: Center for the Study of Language and Information ... CSLI Lecture Notes, no. 59), 1996. ISBN 1-881526-91-7
Donald E. Knuth, Digital Typography (Stanford, California: Center for the Study of Language and Information ... CSLI Lecture Notes, no. 78), 1999. ISBN 1-57586-010-4
Donald E. Knuth, Selected Papers on Analysis of Algorithms (Stanford, California: Center for the Study of Language and Information ... CSLI Lecture Notes, no. 102), 2000. ISBN 1-57586-212-3
Donald E. Knuth, Selected Papers on Computer Languages (Stanford, California: Center for the Study of Language and Information ... CSLI Lecture Notes, no. 139), 2003. ISBN 1-57586-381-2 (cloth), ISBN 1-57586-382-0 (paperback)
Donald E. Knuth, Selected Papers on Discrete Mathematics (Stanford, California: Center for the Study of Language and Information ... CSLI Lecture Notes, no. 106), 2003. ISBN 1-57586-249-2 (cloth), ISBN 1-57586-248-4 (paperback)
Donald E. Knuth, Selected Papers on Design of Algorithms (Stanford, California: Center for the Study of Language and Information ... CSLI Lecture Notes, no. 191), 2010. ISBN 1-57586-583-1 (cloth), ISBN 1-57586-582-3 (paperback)
Donald E. Knuth, Selected Papers on Fun and Games (publication planned in late 2010)
Donald E. Knuth, Surreal Numbers: How Two Ex-Students Turned on to Pure Mathematics and Found Total Happiness. 1974, ISBN 0-201-03812-9. More information can be found at the book's official homepage
Donald E. Knuth, The Stanford GraphBase: A Platform for Combinatorial Computing (New York, ACM Press) 1993. second paperback printing 2009. ISBN 0-321-60632-9
Donald E. Knuth, 3:16 Bible Texts Illuminated (Madison, Wisconsin: A-R Editions), 1990. ISBN 0-89579-252-4
Donald E. Knuth, Things a Computer Scientist Rarely Talks About (Center for the Study of Language and Information ... CSLI Lecture Notes no 136), 2001. ISBN 1-57586-326-X
Interviews and lectures
Video of Donald Knuth's talk at Google, March 16, 2009 - On interactions between faith and science
TUG'95 (St Petersburg, FL, USA) Questions and answers with Prof. Donald E. Knuth. TUGboat 17 (1), 1996
Woehr, J. An interview with Donald Knuth Dr. Dobb's Journal, April 1996, p. 16-22.
Donald Knuth on The Art of Computer Programming Addison-Wesley Innovations, 1996
Questions and Answers with Prof. Donald E. Knuth. Czech TUG, Charles University, Prague, 1996
Knuth meets NTG members, Amsterdam, March 13, 1996.
Knuth Comments on Code, Byte magazine, September 1996.
Donald Knuth: A life's work in the art of programming Amazon.com, 1997.
U.K. TUG, Oxford, September 12, 1999: Question & Answer Session with Donald Knuth. TUGboat, 22 (1/2), 2001.
Dr. Dobb's Audio & Video Archive of Knuth's MMIX and God & Computers Lectures @ MIT, Fall 1999
Donald Knuth: MMIX, A RISC Computer for the New Millennium. Audio recording of a presentation at the monthly meeting of the Boston ACM December 30, 1999
Wallace, Mark. The art of Don E. Knuth Interview on salon.com, 1999.
Things A Computer Scientist Rarely Talks About - Lecture 1: Introduction, October 6, 1999
Advogato, 2000, also available as HTML Version
AMS, 2001
Oslo, 2002
c't, 2002 (in German)
NZZ Folio, 2002 (in German)
Donald Knuth, Founding Artist of Computer Science. Audio interview by David Kestenbaum on National Public Radio; or Transcript, March 14, 2005.
Free Software Magazine interview by Gianluca Pignalberi, August 2005.
InformIT Interview by Andrew Binstock, April 2008.
Communications of the ACM, Vol.51,7 pp.35-39, Interview, part 1 by Len Shustek, July 2008 (An edited extract from the 2007 interview above.)
