SHIKASTA by Doris Lessing
Knopf; 384 pages; $10.95
Science fiction is pastoral turned upside down, radiating a nostalgia not for what was but for what could be. Since this mystic longing has increasingly filled the novels and stories of Author Doris Lessing, 59, it is not surprising that she has finally got around to spaceships and galactic travelers; she herself calls Shikasta, her 24th book, "space fiction." This description is accurate enough, but it may mislead some into expecting much less than this dazzling novel actually delivers. Shikasta owes more to Gulliver's Travels and...