The Sammy Cahn (ne Cohen) story -- from Lower East Side origins to his successful career writing song lyrics up to his current peak as the star of his own life story on Broadway (Words & Music) -- is an unpretentious self-portrait which retains much of the zest of its ""smiling rascal"" of an author. Bitten at an early age by the vaudevillean bug, he supplemented a job taking meat orders with violin gigs at weddings and bar mitzvahs. Setting out to be a songwriter, Cahn ""struggled like hell to stay alive and get going in the business"" as he made the arduous transition from the Catskills to Vitaphone short subjects. Teamed with composers Saul Chaplin, Julie Styne and Jimmy Van Heusen, his intuitive finger-tapping talent was able to surface as he wacked out in a single day the Oscar-winning title songs Three Coins in the Fountain and Call Me Irresponsible. Having survived ulcers and a painful divorce, several ""humbling"" musical flops and the likes of Harry Cohn and Artie Shaw, the author-lyricist only recently fulfilled ""the ham in Sam"" with his autobiographical Broadway triumph. This bagels-to-baubles success story comes straight from Cahn's High-Hoping, Pocketful of Miracling heart.