Wilderness Visions: The Western Theme in Science Fiction Literature

Edited by Daryl F. Mallett. Billed as a "2nd edition, revised and expanded" of "Wilderness Visions: Science Fiction Westerns, Volume One". Originally announced in 1989 as "New Worlds, Old Frontiers: Science Fiction Westerns, Volume II". The latter was apparently never published, although at least 2 libraries still list it as a forthcoming book.

Data from WorldCat. According to OCLC, the price of the hardcover edition was $25.00 at one point, but it's not clear whether that was the original price.