"The real problem is that programmers have spent far too much time worrying about efficiency in the wrong places and at the wrong times; premature optimization is the root of all evil in programming."

“Email is a wonderful thing for people whose role in life is to be on top of things. But not for me; my role is to be on the bottom of things. What I do takes long hours of studying and uninterruptible concentration.”

“Any inaccuracies in this index may be explained by the fact that it has been sorted with the help of a computer.”

“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.”

“How can you own numbers? Numbers belong to the world.”

“If you find that you're spending almost all your time on theory, start turning some attention to practical things; it will improve your theories. If you find that you're spending almost all your time on practice, start turning some attention to theoretical things; it will improve your practice.”

“The whole thing that makes a mathematician’s life worthwhile is that he gets the grudging admiration of three or four colleagues.”