How Things Work
Almost anyone who grew up in Britain will be familiar with Ladybird books - small, thin hardbacks that went from basic reading ("Dick has a ball. See the ball.") to fact-filled fun for older kids such as their "How Things Work" series ("What's this, grandad?" "It's like HowStuffWorks.com in a book." "What's a book?" etc...). Anyway, someone's gone to the trouble of scanning in the 1971 and 1979 editions of How Things Work... The Computer, and they're great. I particularly like the 1971 idea of "A small digital computer designed for the businessman" (top left).