Charles Babbage was an English genius of legendary eccentricity. He invented the cowcatcher, the ophthalmoscope, and the "penny post." He was an expert lock picker, he wrote a ballet, he pursued a vendetta against London organ-grinders that made him the laughingstock of Europe. And all his life he was in desperate need of enormous sums of money to build his fabled reasoning machine, the Difference Engine, the first digital computer in history. To...