If Meryl Streep is truly ""the most reluctant superstar ever to capture the imagination of the American public,"" then why did she contribute interview-quotes (many of them cheerily inane) to this gushy celeb-bio? Maychick tells us, furthermore, that ""Meryl is the first actress with whom ordinary women can truly identify,"" that she has achieved superstardom ""without once allowing herself to luxuriate in acclaim."" Then we go back to Meryl's New Jersey-suburb childhood, to trivia from her big-shot high school days. (""She was a real cutie-pie,"" recalls guidance counselor Ronald Bernard.) Vassar, summer-stock, and Yale Drama followed; fresh out of school she won a role at Joe Papp's Public Theater--with a series of stage triumphs leading to films like Kramer vs. Kramer (she rewrote her dialogue) and The Deer Hunter. (""How did she manage to imbue such an ordinary woman with so much soul?"") National fame came via Holocaust. But her life has had one dark shadow: the cancer-death of her lover/colleague John Cazale (she was ""emotionally blitzed""), followed six months later by marriage to a Soho sculptor. (""She and Gummer conceived their first child on a cold January night in their eclectic Soho loft."") And she was ""devastated"" about not winning an Oscar for French Lieutenant's Woman . . . though the joys of Sophie's Choice victory (and motherhood) have eased that sorrow. Maychick has little to say about Streep's craft, quoting from rave revuews but not from, for instance, Pauline Kael's more critical essays. Still, with movie-by-movie backstage details, interview-anecdotes, and heavy emphasis on regular-gal Streep's utter integrity, this is a harmless enough concoction for adoring fans.