I borrowed an interesting book from the library a while ago: _Information and Secrecy. Vannevar Bush, Ultra, and the Other Memex_. If this is old hat, please ignore. It covers the history of computing and comparing machines from the early 1900's to about 1950 -- devices employing photocells, relays, gas-filled tubes, microfilm, punched optical tape, mechanical integrators, etc. There is a fair amount of crypto relevance as it passes through WWII and the cracking of cyphers becomes important. It's also a tale of overly-ambitious projects that rarely worked, beaurocratic bumbling, influence, and ignorance. _Information and Secrecy. Vannevar Bush, Ultra, and the Other Memex_. Colin Burke The Scarecrow Press Inc. 1994 ISBN 0-8108-2783-2 ------------------------------------------------------------------------- Steven Weller | "The Internet, of course, is more +1 415 390 9732 | than just a place to find pictures | of people having sex with dogs." stevenw@best.com | -- Time Magazine, 3 July 1995