Hijuelos's fluency--whether seamlessly singing the sad ballad of a family harrowed by madness and displacement in his first novel, Our House in the Last World (1985), or the slightly happier, warmer, more infectious up-tempo one of the Pulitzer-winning The Mambo Kings Play Songs of Love (1989)--is his signature, and here he gives it a very, very long solo in a family chronicle that follows a huge Irish-Cuban family across the span of a century. The very title here speaks of muchness, and muchness is delivered--but much, disappointingly, about very little. The eponymous brother is a 1950's B-movie actor who hits the rocks, a pattern of modest success without hope of permanence that began with his Irish-born photographer father and Cuban poetess mother. The Montez O'Briens grow up in a small Pennsylvania town, and Hijuelos follows them out and back--to Cuba, New York, Hollywood, Alaska, Ireland--as they make do individually and together. But as often imperils such a feckless, loose-woven, overly charactered book, Hijuelos pretty quickly gives up trying to invest each sibling with the same detailed attention, focusing instead on the patrician eldest sister, Margarita--a woman of innate dignity and poise--and leaving the rest to serve as mere counterpoints. What Hijuelos seems to want to do more intently is write lyrically, and he does. Sometimes it's good lyricism--as in Mambo Kings, Hijuelos writes about sex with just the right amount of dirty relish and melody--and sometimes it's awful, plunging to the novice level: ``In his sisters' company, he'd experience a sensation of pure happiness and it would seem that everything around them emanated from those females, the world itself a fertile living thing, the earth beneath them humming with its unseen life....'' A family chronicle can manage to achieve both harmony and individuality- -Larry Woiwode's Beyond the Bedroom Wall is an example--but it takes a concentration of imagination that Hijuelos hasn't engaged here. Fat but flat.