The public appetite for Diana books seems to have wavered only slightly since the excellent "Diana" by Julie Burchill was published last year. The ante for Diana spill-alls has gone down, presumably because Burchill seems to have the final word on the subject. Her examination of Diana's life and celebrity is done with a jaundiced eye that is merciless on Charles but also refuses to spare Diana. Of the 110-plus books on the late Princess of Wales, only Burchill's "Diana" comes close to cracking the royal facade. This will come as no surprise to readers who have followed Burchill's career as a thorn in the side of British journalism. Her call-'em-as-she-sees-'em style first came into the limelight with her seminal exploration of punk in the late Seventies, "The Boy Looked at Johnny." Small wonder her view of the royal family is so savage. Burchill isn't the first to pinpoint many of Diana's problems to "the Firm" but she's the one who never lets up on the Windsors. Burchill, who coined the term "the People's Princess," assails them for treating Diana as a brood mare and their cold, unconscionable behavior after her death. And although Burchill always keeps the queen in her sights, she saves the lethal bullets for Prince Charles, repeatedly excoriating him for the "whatever love means" quote he uttered to cameras at their engagement announcement. Burchill's point is that Charles knew all too bloody well what love meant, and when he couldn't have it with his mistress Camilla Parker-Bowles, he got himself a childbearing trophy wife instead. "Diana" is for the true Diana-philes, the ones who accept her faults with her majesty.