On a private adult phone-sex line, Jim, a West Coaster in his late 20s, connects with East Coast Abby. Birds of a feather--both of them witty, obsessive, yuppie masturbators--they're off, trading stories and fantasies and the psychopathologies of everyday life. Baker (The Mezzanine, Room Temperature), heretofore more a monologist, a literary performance artist, than much of a novelist, folds his deadpan honesty and funny fussiness double--and though Jim and Abby finally seem so much like the same voice that they don't really qualify as characters, they don't have to: Baker has found a conceptual format, the phone sex, perfectly tailored to his talents. This is a mini-epic of Big Chill--ed safe-sex: rambling stories that start out as aids to titillation but dry and crumble into homely and self-satisfied details that challenge eroticism; the overturning of classical seduction theory (here, both the man and woman, unseen to each other, know that the other has his/her hand on his/her self); lots of little snappy apercus and joshings establish intellectual coziness. The tropes of modern sex--olive oil, VCRs, copying machines, the letters in Penthouse Forum--are traded breezily, sometimes hilariously, but are nothing compared to the main technological thrill; after Abby tells him exactly how she masturbates in the shower, Jim (in the book's best and most concentrated moment) declares it a miracle, ```a telephone conversation I want to have. I love the telephone.''' And Baker does expose a strange kind of dignity, in that Jim and Abby aren't using each other for very much more than as instruments of exemption from embarrassment. Quite a literary season for self-relief! First Harold Brodkey as the Mahler, the Liszt, of the hand-job, now Nicholson Baker as its David Letterman.