'How it works' The Computer, 1971 | Ladybird

'How it works' The Computer by David Carey with illustrations by B. H. Robinson. Published by Ladybird in 1971.

More pages of a 1978 reprint version here http://gadgets.boingboing.net/2008/12/24/how-it-works-the-com.html or compare both versions side by side here http://davidguy.brinkster.net/computer/