If you want a very detailed account of the super early history of electronic computing, George Dyson's "Turing's Cathedral: The Origins of the Digital Universe."

http://www.amazon.com/Turings-Cathedral-Origins-Digital-Univ...

Other great titles I'd recommend is Steven Levy's "Hackers" http://www.amazon.com/Hackers-Heroes-Computer-Revolution-Ann... and Phil Lapsley's "Exploding the Phone" http://www.amazon.com/Exploding-Phone-Untold-Teenagers-Outla...

Hope you enjoy!