An investigative reporter's harsh--albeit absorbing--appraisal of the darker realities underlying the life-styles of a rich and famous New York City couple. Even without the cooperation of his subjects, Newsday correspondent Moss has managed to compile an impressive dossier on the Helmsleys. By the author's scrupulously documented account, Harry (nÇ Henry in 1909) was for most of his career a tough but legal operator whose eye for property values and mastery of the Internal Revenue Code enabled him to build a coast-to-coast real-estate empire--and a net worth in excess of $1 billion. Until he was smitten by the flamboyant Leona (now 68), Harry took care of business and lived quietly in Westchester County with his first wife, a devout Quaker. The twice-divorced Leona, however, made his an altogether different story. A hard-driving apartment broker once in the employ of a Helmsley subsidiary, she brought a new kind of love to Harry. Wed in 1971, the pair quickly became fixtures on Manhattan's new-money social scene. Harry also ventured into luxury hotelS, a field that gave his ambitious consort an eagerly seized opportunity to make a name for herself (thanks mainly to ads promoting Leona as "Queen" of the Palace chain). Unfortunately, while the king was in the countinghouse or otherwise occupied, his fellow monarch was engaged in a conspiracy to extort money from Helmsley contractors and to evade taxes by billing personal expenses to corporate accounts--at least that's what federal and state prosecutors charged last April, when they brought indictments against the Helmsleys and several associates. While the defendants have not yet had their day in court, Moss convincingly portrays Leona as a designing, mean-spirited woman who has cut a lot of corners, with Harry bearing a considerable burden of guilt for having allowed her, so to speak, free reign. An evenhanded bill of particulars that rings true throughout.