The ever-brilliant Barnes concocts a mordant sexual comedy for his latest novel, taking over the later lives of three characters he introduced in the earlier Talking It Over. Straight, rather stuffy organic-food kingpin Stuart; his former best friend, the ebulliently witty layabout Oliver; and Gillian, whom Oliver stole from Stuart, address the reader in turns about just what happened (or in Oliver`s case, show off for the reader in a dazzling display of verbal pyrotechnics that would bring down the house if this were a play). There`s no doubt that in most ways Stuart deserves Gillian more than Oliver does, and the latter`s attraction for her seems odd. On the other hand, Oliver is, unexpectedly, quite a good father, and there are hints of obtuseness and brutality about Stuart`s bluff self-satisfaction. Poor Gillian, whose French-born mother also comments on the proceedings from a cynical distance, seems quite unable to decide between the two men when Stuart forcibly reenters her life. Out of their often self-serving, sometimes touchingly self-aware accounts of a handful of encounters emerges a funny, occasionally poignant look at the strange confusion between friendship and love--as well as more than a hint that nobody truly knows just who they really are and what they are capable of. It`s slight but telling and, except for Oliver`s wonderful and witty set pieces, oddly subdued for Barnes, but it would make an excellent play, in the Tom Stoppard vein. (Feb. 13) Forecast: Although Barnes`s succession of clever novels have won him a following here, the strongly English domesticity portrayed in Love, Etc. seems unlikely to gather him many new adherents. For connoisseurs of brilliant invective, however, it`s a treat, and Knopf is anticipating that interest with a 40,000 first printing.