Alternate History

Historians have always played the game; the Roman historian Livy wondered what would have happened if Alexander the Great had turned west against Rome. In fiction, L. Sprague de Camp's Lest Darkness Fall (1939) sent a modern archaeologist back to sixth-century Rome to prevent the Dark Ages, and Ward Moore's Bring the Jubilee (1953) imagined a Confederate victory in the American Civil War.

Philip K. Dick's The Man in the High Castle (1962), set in an America divided between Nazi Germany and Imperial Japan, won the Hugo Award and became the form's best-known novel. Keith Roberts' Pavane (1968) imagined a Catholic England where the Reformation never happened.

In the 1990s the form boomed. Harry Turtledove, sometimes called the master of alternate history, sent AK-47s back to the Confederacy in The Guns of the South (1992). Robert Harris' Fatherland (1992) was a detective story in a victorious Nazi Germany, Philip Roth's The Plot Against America (2004) put Charles Lindbergh in the White House, and Michael Chabon's The Yiddish Policemen's Union (2007) imagined a Jewish homeland in Alaska.

Expect a recognisable world bent out of shape: familiar cities with different flags, real historical figures in unfamiliar roles. Much of the pleasure is in detail, and readers who know the history will spot changes and jokes everywhere. The point of divergence is often revealed gradually.

Many alternate histories are thrillers or detective stories, using the genre plot to explore the world. Others are sprawling multi-volume chronicles that follow the change across decades.