From the Publisher
There is no surer way to feel the danger or the good fortune of our collective past than to contemplate those moments when the world's future hung in the balance. Our brightest historians speculate on some of these intriguing crossroads and the ways in which our lives might have been changed for the better -- or the worse.
These unabridged essays range across the full span of history. Geoffrey Parker describes ramifications that might have included a divided Reformation movement, a strengthened Catholic leadership, and no European settlements in the Americas. And Caleb Carr argues that we could have been spared the horrific last six months of World War II in Europe if Eisenhower had seized his chance to destroy the Nazis in the fall of 1944.
This could have been so much more interesting. Most of the descriptions of what if stopped just when it started to become interesting. Or they were too abstract.
I can't comment about the details of most of them, because I didn't know enough about the original events to say how the what if scenarios could have been described in a more interesting way.
The first one, though, was about what if Jesus hadn't died when he said he would, but had lived until he had died at an old age. The author of that essay seemed to think that it would be considered blasphemous to imagine this, but in fact, it's even kind of addressed in the Bible. See 1 Corinthians 15:14 "And if Christ has not been raised, our preaching is useless and so is your faith." There are so many things that could have been addressed, e.g. it is generally believed that without Jesus' death and resurrection, Christianity wouldn't have all developed like it did, but may have slowly died out. The author of the essay in the book, though, seems to believe that Constantine would still have made it the state religion and church fathers would still have met in the 4th century to discuss things the way they did in reality.
In general, I would have expected a descriptions of some exciting differences but in the abstract high level way the essays were written, even for the "what if the potato hadn't been introduced into Europe" you couldn't imagine the consequences too well.