The first 50 pages or so of Greenburg's latest sex-and-satire lest are tautly hilarious--something like an X-rated update on those bright, foolish Hollywood sex comedies of the early Sixties. Lance Lerner, 40-year-old semi-successful writer, is suddenly sure that gorgeous wife Cathy (a Times Book Review editor) is having an affair with Lance's best friend Les. So, naturally, Lance decides he must have an affair with Cathy's best friend--dowdy Margaret, who turns out to be shockingly responsive: she talks dirty to him at Maxwell's Plum, invites him up to her place. . . but, unbeknownst to Lance (who has quickly thrown off all his clothes), Margaret has actually enticed him to a surprise birthday party, with Cathy and 40 friends in now-appalled attendance! And, since it also turns out that Cathy wasn't having an affair, she promptly dumps Lance and goes forth to become her own person (the sex-role stuff throughout is strangely dated). The much less hilarious rest of the book, then, is Lance's post-Cathy life: an episodic mishmash of sex, feminism, therapy, and book-world satire. Lance joins a therapy group--with some familiar but solid laughs. He howls when his forthcoming novel is given only a $5000 publicity budget (enough for ""FM radio in Jersey and Moonie newspapers""); but he wangles a ten-city tour by sexually servicing his publisher's wife in a variety of public places. He goes out with policewoman Stevie, who's into bondage; but she leaves Lance handcuffed to the bed, thus making him vulnerable to rape by Gladys, the elephantine super--who'll get pregnant. He allows a pair of book-groupie teenage lesbians from Chinatown to move in with him (the inevitable threesome ensues--as does one with cocaine-snorting stewardesses). And, throughout, Lance still longs for Cathy, at one point going after her with a police helicopter. Finally, however, as this overlong potpourri slides into comic-book gear, Lance at last gets on Johnny Carson (as a spokesman for the ""Dalton Two,"" a pair of black would-be writers who robbed Dalton's Books); and his flight back to N.Y. is hijacked by MATE (""Men Are The Enemy""), a feminist guerrilla group that castrates men and now forces the plane to land on the matriarchal island of Mannihanni--where dictator Mamma Doc reveals that she too (like everyone else in the novel) wants to be a writer. (Lance, who at last supposedly comes to understand his love/hate/fear of women, will get Cathy back and hit the best-seller list with I Remember Mamma Doc.) Stale on the battle-of-the-sexes, fairly fresh on the book-promo scene: a rambling joke-book that's funny about half the time, as inspired raunchiness alternates with mere grossness on the Playboy-cartoon level.