ECOTOPIA<i> by Ernest Callenbach (Bantam: $8.95) </i>

One of the key books of the ecological movement, Ernest Callenbach’s futuristic novel is composed of newspaper columns by a reporter visiting Ecotopia, 19 years after Northern California, Oregon and Washington have seceded to form a nation dedicated to a “stable-state” ecosystem. Callenbach incorporates many attractive ideas into his version of Erewhon: smaller cities, lots of trees, uncontaminated food. But the thrust of the narrative is weakened by the way the Ecotopians relate to each other. Their telling dialogues read like spoofs from “Doonesbury’s” Institute for the Mellow, and the threat of AIDS has made their sexual promiscuity a hopeless anachronism. “Ecotopia” reminds the reader of the shift in values that has occurred since 1975.