Lucy Rosser--31, N.Y.-born, divorced--is currently (circa 1977) a TV-documentary-maker in L.A., getting all the sex she wants, including the oral brand she prefers. But ""I've had them lapping at me like honey bears and half the time I can't come."" Why not? Because Lucy now wants a baby, wants ""to be entwined in someone's life. . . . I want my nose rubbed in the ordinariness of being a couple."" And she has big hopes for her new relationship with documentary-maker Joe Sachs--bright, gorgeous, super in the sack, sharing Lucy's tastes in drugs and soft drinks. Joe, however, isn't ready for monogamy. (""I'd like to get myself in shape to where I could have a relationship,"" he burbles.) Furthermore, Lucy's in a stew (ill-motivated) about the affair between her ex-hubby and her best pal Pam. So, for the moment, she muddles along--trying to find total satisfaction in her work: she and Joe team up professionally, working on a pretentious film about the anguish of today's singles population. (Tiresome interviews with an assortment of shallow swingers ensue.) But then, after a glimmer of epiphany at Jewish New Year services, Lucy goes to Joe's beloved Israel to make a documentary, sleeps with old-flame Uzi, and undergoes the now-familiar transformation via roots discovery. She learns Israeli history, reads the Bible, sightsees; ""she saw herself as part of this living chain that reached all the way back to the nomads who had wandered in this desert. . . and she thought, Lord, don't let it end in me. . . I want to be connected to the river that flows on. . . . She cried out with all her soul, and she heard an answer: You will."" When Joe joins her in Israel, they wind up stranded together in the Sinai wilderness, surviving an ordeal of thirst and bad dialogue. (""Don't you understand? This is a desert, this is not some goddamned singles bar."") And though this trek/encounter-session does finally bring Joe to Full Relationship level, it's ""too late"": a limp last-page epilogue tells us that Lucy will marry somebody else--presumably happily ever after (though readers will have their doubts). Everything that Davidson does here has been done so much better elsewhere: the post-30 motherhood yen, the singles yearning for Commitment, the Jewish ethnic/spiritual rebirth. Both Lucy and Joe are uncommonly shallow, defined largely in terms of brand names and psychobabble. Except for an occasionally funny line, the talk is crass or dull; so is the sex. But the Loose Change byline will draw some attention--and there's a modicum of surface commercial appeal here, especially in areas where Davidson's built-in audiences (That Cosmopolitan Girl, That Hadassah Woman) overlap.