Some people might call 'It's Only A Play' a valentine to the theater, but you mustn't believe them. Terrance McNally's play is not so much a love letter from a shy, smitten admirer as a mash note sent by a stalker who's written it in capital letters and smeared it with what may be bodily fluids. Whatever it is, it's a pure hoot, a rollicking comedy with perfect casting and deft direction in Jack O'Brien that gleefully dissects modern Broadway and doesn't pretend to mask its targets by using fake names...Lane is the unquestionable star here, at his droll best with perfect timing, mugging when he needs to or raising a haughty eyebrow to sell a joke the next. The rest of the cast -- including a really remarkable Broadway debut by Stock in a company of powerful stars -- is superb, all hysterical at first and then revealing deeper desires as the play continues.