Though not nearly as distinctive as Davis-Goff's more serious first novel Night Tennis (1978), this dry, breezily episodic spin through the lives of two young non-American women in N.Y.C. turns some awfully familiar material into a modestly funny, sneakily sad graph of up-and-down romantic fortunes. Not-so-pretty Diane is 29, a Protestant from Ireland, an Oxford dropout who types for adored, non-adoring writer Philip and shares a filthy apartment with tart stewardess Claire (who gets all the good Eve Arden lines). Very pretty Sandy, on the other hand, is around 20, a Catholic from England, a ""Grade A survivor"" who steals boyfriends, never pays back loans, but holds onto Diane's chumship with her cheery forthrightness. In fact, when Sandy (now calling herself Alexandra) suddenly meets and marries Philip--after her live-in engagement with plump Dennis and his rich Westchester ""Mom""--jealous Diane stays on as their secretary-nanny; true, she takes some petty revenge (""she neatly folded a letter to a New York Review of Books critic which contained two gross spelling mistakes, sealed the envelope and put it in her out tray""), but she makes herself indispensable . . . especially after baby Tania is born. So, when Sandy (now calling herself Alexis) runs off with high-rolling gambler John, Diane is quite ready, thank you, to become Philip's wife and Tania's loving stepmom. But both women, quite soon, will be adrift again: John dumps Sandy, who takes up real-estate (half-heartedly) and party-girling (unintentionally); Diane loses her bearings in adulterous doings (including mÃ‰nage Ã trois) with all-sex, no-love David. And at the fadeout La Ronde is beginning yet again, as Diane eyes sweet movie-producer Mitch (for whom she has done freelance scriptreading) while Sandy moves in the same direction with, as usual, far more courtesanly effectiveness. No great depth, perhaps, but no great puddles of psychological stewing either: a likable, ironic yet soft-edged comedy of sighs, taking one of romantic fiction's standbys--the bright, sedate girl vs. the dumb, sexy girl--for a quick, skittery, fairly fresh ride.