Chaplin: Last of the Clowns, byParker Tyler. Illustrated with Photographs (Vanguard Press; $3). Parker Tyler’s Chaplin, Last of the Clowns, has all the virtues and weaknesses of his earlier books. It is an inextricable blend of real depth and false glamor. Reading this book is like riding on a seesaw: at one moment you are fascinated by the author and at the next exceedingly irritated. Tyler conceives Chaplin as a clown with an alter ego.