Another predictable hour or two with the professionally genial Coz, concocted on the lite formula perfected in previous books (Fatherhood, Love and Marriage) anent The Ages of Man and A Few Women. Coolly calculated to be heartwarming, the present text recounts Cosby's North Philadelphia childhood under the aegis of Mom and Dad, with appearances by brother Russell and others, including, of course, Weird Harold and Fat Albert. Contrasted with the independent street antics of a generation ago is the Nintendo self-absorption of the current Cosby kids, from which nearly hilarious results ensue, as the sitcoms would have it. ``As I have discovered by examining my past,'' begins the author, ``I started out as a child.'' Dissolve from that auspicious opening to scenes of instruction in manners (``keep your face outa the soup''), animals (``It's a very special thing to have a gypsy moth for pet''), and the fine points of gentlemanly sports (like after- school fighting). If the one-liners begin to sound like George Burns, the result is benign. From musical beds with Russell to a pubescent hunt for fabled Spanish Fly, it's all contrived and easy enough reading for both those now caught in the undertow of childhood and their seniors who somehow survived it long ago. With a book that's transparent, easily digested, low calorie, and inoffensive, Cosby is still selling Jell-O. For fans of Mr. Nice Guy.