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

I've never been a good estimator of how long things are going to take.

TeX has found at least one bug in every Pascal compiler it's been run on, I think, and at least two in every C compiler

We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. Yet we should not pass up our opportunities in that critical 3%

A list is only as strong as its weakest link.

When you write a program, think of it primarily as a work of literature. You're trying to write something that human beings are going to read. Don't think of it primarily as something a computer is going to follow. The more effective you are at making your program readable, the more effective it's going to be: You'll understand it today, you'll understand it next week, and your successors who are going to maintain and modify it will understand it.

The process of preparing programs for a digital computer is especially attractive, not only because it can economically and scientifically rewarding, but also because it can be an aesthetic experience much like composing poetry or music.