Code

Charles Petzold's 1999 account of how computers work at the deepest level — from Morse code and Braille through logic gates, flip-flops, and machine language to operating systems — the clearest explanation of computation for non-engineers.

Makes the entire stack of computation comprehensible to non-engineers — Petzold builds from human communication systems through electrical circuits to modern computers using no math beyond simple logic, giving readers a true mental model of how software and hardware connect.