During a five-year period the Master Jazz label recorded 11 swing-based pianists in solo settings. Although the label went under later in the decade, the recordings were treasured by collectors. Mosaic, on this four-CD set, brought back all of the music from the original five-volume Master Jazz Piano series, adding two unissued selections and a full album released separately of Ram Ramirez's playing. In addition to Ramirez (who is heard on 13 numbers), there are 13 performances by Earl Hines, four apiece from Claude Hopkins, Cliff Jackson, Keith Dunham, Sonny White, Teddy Wilson, Cliff Smalls and the obscure Gloria Hearn, eight by Jay McShann and two from Sir Charles Thompson. Most of these pianists (other than Hines and Wilson) rarely recorded during this period in their careers, making this box very important both musically and historically.