What If?, subtitled The World's Foremost Military Historians Imagine What Might Have Been, is a collection of twenty essays and thirteen sidebars dealing with counterfactual history. It was published by G.P. Putnam's Sons in 1999, ISBN 0-399-14576-1, and this book as well as its two sequels, What If? 2 and What Ifs? of American History, were edited by Robert Cowley. It was later combined with What If? 2 to form The Collected What If?.