The Baby Boom were mostly still in their cradles or unborn when The Bachelor and the Bobby-Soxer came out in 1947, which makes the film a historical document – one of our first glimpses of a generation gap forming in postwar America. The whole idea of the teenager is really less than a century old, and by the late '40s it was edging out the "bobby-soxer" – a largely female phenomenon that was launched into public consciousness with the shrieking fans who descended on Frank Sinatra's performances at the Paramount Theater in New York during the war. In his book...