Donald Ervin Knuth is turning 85 today. He is one of the most fascinating persons in the Computer Science world to me. Let’s indulge as I am telling you my favourite facts about him. Fact #1: One Book, One Life # When he was 24, Don Knuth agreed to write a book about compilers. You know, something straightforward, à la “Compilers in action”: chapter 1 Lexers, chapter 2 Parsers, chapter 3 Generation, etc.