Various Artists

Forget what the pop music writers tell you -- the first concept album of the long-play era was not Pet Sounds, Sgt. Pepper or Only the Lonely; it was an instrumental album, and its genesis came from, of all things, a piano industry study.

In 1950 Columbia Records executives learned that more homes had pianos than record players. At the same time, there were, per capita, fewer people actually playing the instrument. The message was clear: The piano was losing its position as a home entertainment centerpiece. Radio, television and the phonograph, none of which required any talent to use, were supplanting the piano, which called for years of practice to play with any respectability.

With that information in hand, producer George Avakian and crew developed the first concept series of the long-play era: Piano Moods, which was essentially a brand name under which 20 albums were released. Each disc was by a pianist popular at the time, ranging from jazz heavyweights like Erroll Garner, Teddy Wilson and Earl Hines to "society" pianists like Nat Brandwynne and Cy Walter.

The pianists played in trio formats (usually with bass and drum accompaniment), and the piano took center stage on every piece. Many of the albums were cut without pauses between the songs, as the pianists created bridges between tunes. Thus each side consisted of 15 to 20 minutes of uninterrupted music. The discs provided great background music, but they also provided, for those who listened close enough, some deep playing. In the end, several terrific jazz performances were documented under the Piano Moods umbrella. Yet many of these sessions have been out of print for almost five decades. For some reason they never got touched during the various reissue crazes.

Leave it to Mosaic Records, the music industry's greatest jazz preservationist, to come to the rescue. The label has reissued the 12 jazz Piano Moods albums as part of a seven-CD boxed set (sessions by society pianists are not included). The box contains a number of undiscovered treasures. Performances by Hines, Garner and Wilson are typically exceptional -- did these guys ever have bad nights? -- while recordings from several players since forgotten by the jazz mainstream are interesting finds.

Bill Clifton's name, for example, isn't tossed around much, but his impact is felt to this day. He had amazing command of the instrument and influenced a young pianist named Bill Evans. The Clifton session is filled with advanced bebop harmonies and a happy sense of swing. The other pianists here include Buddy Weed (who gave cocktail music a good name), Stan Freeman (a technical wizard), Eddie Heywood (a unique stylist, combining a pop sense with jazz), Mix Miller (a Chicago legend), Joe Sullivan, Jess Stacy, Joe Bushkin and Ralph Sutton.

The box also contains bonus material from the Columbia archives, including Ralph Sutton Plays the Music of Fats Waller from 1951, eight songs from a very young Ahmad Jamal recorded in '51 and '52, and a hard-to-find 1949 concert by the piano's true master Art Tatum. It's educational to draw the connecting lines between Garner and Wilson, Tatum and Hines, etc., and to crisscross the lines between all of the pianists on this seven-CD set. For the fan, student or practitioner of jazz piano, this is an indispensable find, as it reveals many fine performances that have been gathering dust for decades. Besides that, the playing is just killer throughout.