Was Dorothy Kilgallen murdered because she'd learned too much about the Kennedy assassination? Pursuing that theory for three years, Israel (Miss Tallulah Bankhead, 1972), found out enough about the media maven to pad out this fat book and only enough about her 1965 barbiturate-and-alcohol death to strongly suggest that it wasn't the accident it was made to appear. The result is not just another addition to the assassination-hypothesis shelf, however, or overmuch attention to a tinny personality of passing import. What Israel has done is to punch this unpromising, rather incongruent material into some sort of dramatic shape. We have first Dorothy the good Catholic and girlish flirt with a whim of iron -- Hearst reporter Jim Kilgallen's pride and joy -- whose round-the-world race makes her a hot newspaper property; Dorothy the white-gloved pillar of cafe society and -- after her marriage to actor/producer/putterer Richard Kollmar -- the snob at the breakfast-table mike; Dorothy the demon competitor of ""What's My Line?,"" playing the ""unwitting villain"" to Arlene Francis' sweetie-pie. ""Why can't I be the adorable one?,"" she'd complain to Francis; and with that glint of vulnerability, Israel's account -- hitherto as snide, often, as Kilgallen's Broadway columns -- begins to shift a little sympathy toward her. With footloose Dick off ""whoring,"" her marriage has become all show. Prim, uptight Dorothy is incapable, as always, ""of confronting the wellsprings of her emotions"" (i.e., of taking a stand) and now, in her forties, assailed by ""repressed but increasingly querulous sexuality."" (The book's use of language is somewhat bizarre -- ""adversative man"" for adversary, ""emplacement"" for placing on, etc.) She has a torrid, flagrant affair with young singer Johnnie Ray -- and, under his influence, comes into unabashed contact with the likes of Lenny Bruce (whom she'll defend, strikingly, at his trial for obscenity). Frank Sinatra, smarting from many slurs, ridicules her onstage as a ""chinless wonder,"" and all the Dorothy-haters rally: she has to face up to the distaste she inspires. Reeling from too many pills and too much booze, she's repeatedly hospitalized; but, parted from Johnny, she's back to covering murder trials, involved with a new, unnamed man, and hotly in pursuit of Kennedy dope (after a hush-hush interview with Jack Ruby) when . . . she's found dead, all made up for the cameras. The verdict may well be suicide (a more likely reason for a family cover-up), but never mind -- once past Kilgallen's ""vinegary salad days,"" it all makes for a crudely effective, if inflated, tabloid serial.