Mildly, sporadically amusing New York/publishing humor, in the familiar all-letters format--as very young paperback-romance editor Mary writes to her friends, her family, her colleagues, her landlord. . . and her anonymous admirer. So there are routines here, mostly stale, about apartment living--the cockroaches, the studio-apartment crunch, waiting for furniture deliveries. There are jokes about Mary's love life: ""I swear to you that every man I come in contact with is crazy or impotent or both. . . I've had two boyfriends go gay on me. . . ."" There are periodic updates on her new love, playwright Lance, who takes her to an est-like therapy weekend and often slips away to play gigolo to a middle-aged patroness. There are gags about incipient lesbian pal Peggy and her foul lover Alonso (they come for a farcical visit), about sexually frustrated brother Charles (an undergrad), about gay chum Mark (who wants Mary to help him practice heterosexuality), about banking foul-ups, etc., etc. And the subplot about Mary's unsettling mash notes from a stranger ends predictably: Mr. X. turns out to be a fellow editor whom she's never liked. . . but now will love. All of this is basically old-hat, of course, though wilfully trendy (gynecological minutiae, Adidas sneakers)--and the epistolary premise is more strained here than usual, with Mary writing lengthy missives to local people whom she'd much more probably call on the phone (Gwynn sometimes creates contrived excuses for Mary's apparent Ma Bell phobia). But the paperback-romance biz does furnish a few very good chuckles: ""I have marked the 103 places when her 'pulse beat a rapid tattoo' and wonder if you might change some of them"". . . ""I took your dedication out. 'To the destruction of women everywhere' is simply not appropriate for this book."" And those with a weakness for Gall Parent-style yocks, here in a bland but likable version, will smile often enough to make this a painless little pleaser.