Contents: vii • Introduction (Robert Adams' Book of Alternate Worlds) • essay by Robert Adams 9 • The Other World • (1949) • novella by Murray Leinster 93 • Target: Berlin! • (1976) • novelette by George Alec Effinger 119 • Adept's Gambit • [Fafhrd and the Gray Mouser] • (1947) • novella by Fritz Leiber 201 • Last Enemy • [Paratime Police] • (1950) • novella by H. Beam Piper 261 • Aristotle and the Gun • (1958) • novelette by L. Sprague de Camp 294 • There's a Wolf in My Time Machine • [Svetz] • (1971) • shortstory by Larry Niven 311 • Many Mansions • (1973) • novelette by Robert Silverberg 336 • Remember the Alamo! • (1961) • shortstory by T. R. Fehrenbach 347 • One Way Street • (1953) • shortstory by Jerome Bixby