Land's End

Two of SF's liveliest veterans here collaborate on a postholocaust novel that shoots off into unexpected channels. The authors portray idyllic undersea cities where ocean beds are farmed and giant squid are trained as intelligent helpmates, in contrast to the overpopulated landmasses, swayed by demagoguery. Catastrophe comes not from war, however, but from a comet whose debris burns off the atmosphere, creating a deadly ``ozone summer.'' Survivors encounter the mixed blessing of new, alien-controlled leaders who feed and house them for their labor on the vast project of building a spaceship so that an alien life form, called the Eternallong dormant beneath the sea and activated by the comet explosioncan resume its interstellar journey. This is an odd, often dour novel that encompasses but doesn't quite meld its underwater utopia, comically petty tyrants and the doggedly optimistic ``we will prevail'' determination of its characters. (August)