Playgrounds of the Mind

A followup to last year's N-Space , this large and varied collection from hard science fiction master Niven displays the strengths and the weaknesses of that subgenre. With stories such as ``The Soft Weapon,'' in which the hero must solve the mystery of an alien artifact to save himself and his companions, and ``Becalmed in Hell,'' where two explorers on Venus find themselves in peril, Niven provides the old-fashioned SF pleasures of intellectual problem-solving and rigorously depicted astronomical wonders. The ``Draco's Tavern'' series of brief thought-pieces, set in a multispecies spaceport bar, explore larger philosophical questions. But in focusing his attention on accurate scientific detail and describing the marvels of space, Niven often neglects matters of characterization and literary style, and his marginalization of female characters is unfortunate. Excerpts from Niven's novels are included, but they aren't long enough to convey the feel of the larger works, and the self-congratulatory, repetitive snippets of autobiography and science fiction convention memories add very little. Readers should stick to the short stories, many of which are exemplary hard science fiction; ``Ramer'' and ``Wait It Out,'' for instance, are especially rewarding. (Oct.)