The Difference Engine: Charles Babbage and the Quest to Build the First Computer
by Doron Swade, Viking, 2000

Working my way through this book at the moment. I knew a little about Babbage and the Difference Engine, but now I am getting the full story from beginning to end.

Quite a story, filled with the typical intrigues, financial problems and ultimate failure to complete the Engine.( I don't think I am giving away the ending since most tech folks know about this subject.) The first working Engine was completed in 1991 by the Science Museum, London.