The Martian Chronicles, Ray Bradbury (Avon 2/97, $15.00, hc) Classic collection of linked tales exploring human hopes and dreams, and alien enigmas on the Red Planet, with a new introduction by the author. Some of the stories have been ''updated and revised,'' their dates pushed back 31 years. This edition also drops ''Way in the Middle of the Air'', but adds ''The Wilderness'' from the 1973 Doubleday edition.

The Final Encyclopedia, Vol. One, Gordon R. Dickson (Tor 1/97, $25.95, hc) This revised and corrected version of the first half of the 1984 major novel in the ''Childe Cycle'' is one of Dickson's most provocative works.

The Final Encyclopedia, Vol. Two, Gordon R. Dickson (Tor 2/97, $25.95, hc) This revised and corrected version of the second half of the 1984 major novel in the ''Childe Cycle'' is one of Dickson's most provocative works.

Foundation's Friends, Martin H. Greenberg, ed. (Tor 8/97, $9.99, tp) This revised, expanded edition of an anthology honoring Isaac Asimov on the 50th anniversary of his entry into the SF field includes the whole of the original 1989 publication, adding three of Asimov's favorites among his own stories, plus a host of appreciations and memoirs of the late Asimov, one of SF's most beloved masters.

Isaac Asimov: The Foundations of Science Fiction; Revised Edition, James Gunn (Scarecrow Press 2/97, $36.00, hc) Expanded edition of a study which first appeared in 1982, and won a non-fiction Hugo. Includes articles on his major works, an Asimov chronology, checklist, and select bibliography. There is a new chapter on Asimov's bestselling late novels, plus the text of an earlier interview.

The Road to Science Fiction, Vol.4: From Here to Forever, James Gunn, ed. (White Wolf 2/97, $14.99, tp) New edition of one of the classic SF teaching anthologies, first published in 1982, with 31 stories ranging from the '50s to the early '80s, and authors from Benford and Borges to Lem, Vance, and Wolfe, all with critical introductions.

Winterlong, Elizabeth Hand (HarperPrism 7/97, $10.00, tp) Hand's sensually provocative and ambitious first novel (1990) of a strange, post-apocalyptic Earth is finally available again.

The Nature of Smoke, Anne Harris (Tor 7/97, $13.95, tp) Chaos theory meets riot grrls in this hard-edged near future. A first novel we missed reviewing last year when it appeared in hardcover. A belated recommendation.

In Search of Wonder, Damon Knight (Advent 1/97, $20.00, hc) Expanded, revised third edition of a classic gathering of essays on the SF field, with six new essays, including autobiography, coverage of Clarion, and a piece on writing SF.

A Canticle for Leibowitz, Walter M. Miller, Jr. (Bantam Spectra 10/97, $11.95, tp) Return of a remarkable SF classic, well-deserved winner of a 1961 Hugo.

Bring the Jubilee, Ward Moore (Del Rey 10/97, $11.00, tp) Long before Harry Turtledove turned to alternate history, Moore wrote this classic novel of a very different War Between the States.

Triplanetary, Edward E. Smith, Ph.D. (Old Earth Books, 12/97, $15.00, tp) Facsimile of the 1948 first edition of ''Doc'' Smith's first ''Lensman'' book, a classic SF adventure novel.

Vacuum Flowers, Michael Swanwick (Ace 5/97, $5.99, pb) Early cyberpunk tale (1987) of a high-tech fugitive amid Earth's orbiting settlements, an effective mix of drama, adventure, and future technologies.

The Demon Princes, Volume One, Jack Vance (Tor 5/97, $18.95, tp) Omnibus edition of the first three novels in Vance's rousing and inventive SF adventure series, The Star King (1964), The Killing Machine (1964), and The Palace of Love (1967), all featuring Kirth Gerson on his quest to avenge the deaths of his family and his world by hunting down the five galactic outlaws who led the Mount Pleasant Massacre.

The Island of Doctor Death and Other Stories and Other Stories, Gene Wolfe (Orb 8/97, $14.95, tp) This 1980 collection shows that the Wolfe writing SF and fantasy stories in the '70s was as brilliant, witty, and unpredictable as today's master.