According to Gene Wolfe, who flirts with alternate history himself in his Wizard Knight and other fantasy series, Harry Turtledove is more than a master: “Alternate history was once considered a freak, a half-shameful thing to be shoved into a corner and, if possible, forgotten. It is a major genre now, thanks to one man: Harry Turtledove.”

Born in Los Angeles in 1949, Turtledove earned a Ph.D. in Byzantine history from U.C.L.A. Since he began his writing career in 1979 with two mass market titles, Wereblood and Werenight (both Belmont Tower), under the pseudonym Eric G. Iverson, he has published dozens of novels, most part of extended series, many stand-alones and some collaborations. The first book in his Videssos Cycle, The Misplaced Legion (Del Rey, 1987), which draws on Turtledove’s knowledge of Byzantine history, sends one of Julius Caesar’s Roman legions into a world of magic.

In his Worldwar tetralogy and Colonization trilogy, lizardlike aliens invade Earth, interrupt World War II and establish colonies. Homeward Bound (Del Rey, 2004), the most recent and possibly concluding volume in the series, explores the social interactions between humans and lizards as a human starship heads for the lizards’ planet of origin.

Even more ambitious is the series that examines the repercussions of a Southern victory in the Civil War into the 20th century, starting with How Few Remain (Del Rey, 1997), which won Turtledove his first Sidewise Award and owes much to Ward Moore’s 1953 novel Bring the Jubilee (Farrar, Straus), in which a triumphant Confederacy expands into Mexico and Latin America. In Turtledove’s 11th and final volume, In at the Death (Del Rey, 2007), set during the World War II era, the North finally gets revenge.

Ruled Britannia (NAL, 2002), about the aftermath of a successful Spanish invasion of England in Shakespeare’s day, won him a second Sidewise Award. A duology, Days of Infamy (NAL, 2004) and End of the Beginning (NAL, 2005), supposes the Japanese conquered and occupied Hawaii during World War II.

Turtledove shows no sign of slackening his pace. Opening Atlantis (Roc, 2007) launches a trilogy set in the mythical continent of Atlantis. The latest are The Valley-Westside War (Tor), the sixth entry in his Crosstime Traffic series for young adults, and The Man with the IronHeart (Del Rey), a stand-alone in which Himmler’s ruthless deputy, Reinhard Heydrich, survives assassination in 1942 to lead a guerrilla movement against the Allies after Germany’s defeat in World War II.

Betsy Mitchell, Del Rey’s editor-in-chief, explains his appeal: “Harry is a master at teasing out all the strands of story that extended from any particular history-changing premise. His novels illustrate the differences radiating from his ‘what-ifs,’ not just through what happens to history’s famous names but by showing us changes in the lives of everyday workers as well: secretaries, truck drivers, soldiers in the trenches. It’s the richness of his vision that has earned him so many fans.”