Cover art
Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 1: Alternate Empires. Bantam/Spectra 1989 (cover art by Paul Swendsen).
Cover art
Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 1: Alternate Empires. BP/ibooks 2004 (cover art by Dave Seeley).

Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been?
Series note: Anthology series in four volumes, Alternate Empires, Alternate Heroes, Alternate Wards and Alternate Americas..

Cover art
Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 2: Alternate Heroes. BP/ibooks 2004.
Cover art
Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 3: Alternate Wars. BP/ibooks 2004.

Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 1: Alternate Empires
Summary: New stories, including Poul Anderson's "In the House of Sorrows", Gregory Benford's "We Could Do Worse", George Alec Effinger's "Everything but Honor", Karen Joy Fowler's "Game Night at the Fox and Goose", Barry N. Malzberg's "All Assassins", James Morrow's "Bible Stories for Adults, No. 31: The Covenant", Larry Niven's "The Return of William Proxmire", Frederick Pohl's "Waiting for the Olympians", Kim Stanley Robinson's "Remaking History", Robert Silverberg's "To the Promised Land", and Harry Turtledove's "Counting Potsherds". Also includes one non-allohistorical work by James P. Hogan.
Published: Bantam/Spectra 1989 (0553278452BUY); BP/ibooks 2004 (074348729XBUY).
Published: Included in What Might Have Been, Volumes I and II, SFBC 1990.

Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 2: Alternate Heroes
Summary: New stories exploring the Great Man hypothesis, including Michael Cassutt's "Mules in Horses' Harness", Sheila Finch's "Old Man and C", Harry Harrison and Tom Shippey's "Letter from the Pope", M. Laidlaw's "His Powder'd Wig, His Crown of Thornes", Barry N. Malzberg's "Another Goddamned Showboat", James Morrow's "Abe Lincoln in McDonald's", Rudy Rucker and Paul Di Filippo's "Instability" Susan Shwartz's "Loose Cannon", Robert Silverberg's "A Sleep and a Forgetting", Judith Tarr's "Roncesvalles", Harry Turtledove's "Departures", Walter Jon Williams's "No Spot of Ground", and George Zebrowski's "Lenin in Odessa".
Published: Bantam/Spectra 1990 (0553282794BUY); BP/ibooks 2004 (0743487370BUY).
Published: Included in What Might Have Been, Volumes I and II, SFBC 1990.

Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 3: Alternate Wars
Summary: New stories and a reprint exploring results of battles/wars, including Poul Anderson's "When Free Men Shall Stand", Gregory Benford's "Manassas, Again", F.M. Busby's "Tundra Moss", Winston S. Churchill's "If Lee had not Won the Battle of Gettysburg", Nancy Kress's "And Wild for to Hold", Barry N. Malzberg's "Turpentine", Jack McDevitt's "The Tomb", James Morrow's "Arms and the Woman", Mike Resnick's "Over There", Allen Steele's "Goddard's People", Harry Turtledove's "Ready for the Fatherland", and George Zebrowski's "The Number of the Sand".
Published: Bantam/Spectra 1991 (0553290088BUY); BP/ibooks 2004 (0743497864BUY).
Published: Included in What Might Have Been, Volumes III and IV, SFBC 1992.

Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 4: Alternate Americas
Summary: Semi-new stories to mark the quincentennial of Columbus's first voyage, including A.A. Attanasio's "Ink from the New Moon", L. Sprague de Camp's "The Round-Eyed Barbarians", George Eklund's "The Karamazov Caper", Sheila Finch's "If There Be Cause", Esther Friesner's "Such a Deal", Barry N. Malzberg's "Ship Full of Jews", J. Oltion's "Red Alert", Pamela Sargent's "The Sleeping Serpent", Robert Silverberg's "Looking for the Fountain", Harry Turtledove's "Report of the Special Committee on the Quality of Life", and George Zebrowski's "Let Time Shape".
Published: Bantam/Spectra 1992 (055329007XBUY).
Published: Included in What Might Have Been, Volumes III and IV, SFBC 1992.

Cover art
Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 2: Alternate Heroes. Bantam/Spectra 1990 (cover art by Paul Swendsen).
Cover art
Benford, Gregory, and Martin H. Greenberg (eds.). What Might Have Been? Volume 3: Alternate Wars. Bantam/Spectra 1991 (cover art by Paul Swendsen).