I recently learned about Tommy Flowers and Colossus from this book: http://www.amazon.com/Colossus-secrets-Bletchley-code-breaki... The British kept Colossus secret for a too long and Flowers did not get enough credit (and von Neumann seems to get too much). BTW, I do recommend the above book. But we warned that it's a collection of essays by different authors so it can be uneven reading.