Michael Sells brand new Imagine That series#151;short, popular histories of how the past didn't quite happen#151;launches with four titles this year.

Each book is a flight of imagination that explores how the smallest changes to history could have spiraled out of control.

Would a happy ending to Casablanca have led to a more prejudiced world? Would the death of a cat have been the most costly road accident in the history of technology?

Imagine That . . .