Frank Sinatra - In The Wee Small Hours

Recorded in 1955, this superbly arranged and sung set of slow ballads can lay claim to being the first "concept album." Of course, in classical music, song cycles had been around since Schubert, but a whole set of pop tunes arranged around a central theme or mood was something new in popular music. With the advent of the LP in 1953, commercial pop music was beginning to take itself seriously. As to be expected, Frank Sinatra did it first and best.