Robert J. Sawyer's book is not what you think and I think more books should be that way. At first it feels like historical fiction - exceptionally thorough and well-researched. Then it bends a bit, giving us the alternative hinted at the title. By the end, though, the book is something else all together. I will give nothing away, other than my admiration. This novel is like a painting that you first encounter three inches from your nose. You can't fully appreciate it until you've backed up. Or, in this case, read through to the end. Loved it.
I read the electronic version, not that the method matters much, other than the ability to search things, which came in handy.
The Oppenheimer Alternative, by Robert J. Sawyer.