Grace

Grace Robert Lacey (Putnam, $24.95) There's not much grace in Grace. Robert Lacey claims his ''intrusive and unforgiving analysis'' reveals, for the first time, that Grace Kelly was only human. When young she took older lovers, and when older she took young lovers. Grace rejected women's lib, ate and drank too much, and married into an inconsequential royal family with a shameful < past. But we knew all that. We also knew that being merely human never dimmed Grace's lustrous appeal-a point Lacey barely fathoms. Apparently vexed by women's desires, he's obsessed with ''the contradiction of Grace's sexual appetite and the chastity of her public image,'' and he tries to titillate with lines like ''clad only in the skimpiest underwear.'' He worries too much about what Princess Grace might have done in the dark and too little about illuminating why she was important. D -D.A. Ball