Donald Knuth

Donald Knuth (born 1938) is an American computer scientist often called the "father of algorithm analysis." He is the author of the legendary, still-unfinished book series The Art of Computer Programming, and a man so devoted to getting things exactly right that he built his own typesetting system rather than accept ugly printed maths.

The headline achievement

Knuth turned the study of algorithm efficiency into a rigorous science, and he popularised the big-O notation we now use to talk about how fast an algorithm grows. When he grew frustrated with how his equations looked in print, he took a "short" break to write the TeX typesetting system — which took him nearly a decade and is still what mathematicians and scientists use today.

Knuth mails a cheque for a "hexadecimal dollar" — $2.56 — to anyone who finds an error in his books. The cheques became such prized trophies that most people frame them instead of cashing them. He also gave up email in 1990 to protect his focus, warned that "premature optimization is the root of all evil," and once joked that he'd finish his book series before the last computer forgets how to run it.