BOOK REVIEW / ESSAYS : Insights From a Grown-Up Curmudgeon : IF YOU LEAVE ME, CAN I COME TOO?, <i> by Cynthia Heimel</i> , Atlantic Monthly Press, $20, 288 pages

The phrase “I laughed till it hurt” comes to mind when reading “If You Leave Me, Can I Come Too?” humor essays by the only old-guard feminist I can think of who manages to write for Playboy magazine and lives with the contradiction. Perhaps the one thing trickier than coming to terms with the venue (OK, she’s smart: It is a great way to reach a lot of guys) is finding something funny about the Newtering of America.

Cynthia Heimel studies the modern boy-girl landscape and finds it a strange, strained place, the sort that might make a grown woman cry, not laugh: Men are obsolete; the ones you can depend on are as dull as lite cream cheese; women over 40 are invisible except to each other, which is why they dress up and schedule Girls’ Night Out; but if you’re younger, you can’t walk into the bank without enduring the appraising once-over from some hormone-clogged guy.

Not a pretty picture. It has even turned dame against dame. Heimel faults the feminist ex-hippies of her generation for being sanctimonious about the hell they went through for their younger sisters, even though a hell that featured relatively safe sex, comfortable clothes and great rock ‘n’ roll doesn’t sound so bad, in retrospect. She gripes that the new crop of politicos doesn’t get it, either.

Her anger is what makes this collection of essays both vivid and uneven--the former, because there is an intelligent, informed passion behind her jokes; the latter, because funny words can’t always cover up social grotesqueries.

When she maintains the balance between funny and futile, her lines are barbed delights. In “Good Old Days: Fact or Fiction,” she skewers the empty-headed nostalgia where her contemporaries hide from the cold truth.

“For every acid-head freak who is now a happy entrepreneur in Marin County,” she writes, “there is another acid casualty who is his janitor. For every righteous hippie with enough moral fiber to turn her back on capitalist culture, to stick to her back-to-the-land commie ways, there are one thousand mired in the conundrums of whether they’ll ever be able to afford a Jaguar and do they really have to stop wearing fur?”

In the less successful “Girls Night Out: Why?” she veers toward predictability. The issue of whether she’s better off without a guy than are her married and newly mothering friends is too easy a shot, and the prose seems comparatively slack.

Heimel’s been writing funny for years, but this collection marks a subtle change. She’s angrier. She has points to make.

Her indignation ages well; she’s a grown-up curmudgeon. Maybe someday she’ll set aside the short form and really let ‘er rip.

In the meantime, this acerbic set ought to be required reading for anyone who’s frightened by the new status quo--as well as members of that quo, lest they become even more smug than they already are.