What distinguishes this latest reissue of some of the most important recordings in modern jazz from all other previous releases is the inclusion of the September 4 and 18, 1948, airchecks from New York’s Royal Roost, as captured four months before the first Capitol session. Traditionally thought to have been recorded in his home studio through direct phone wire by Boris Rose and much later on bootleg LPs both here and abroad, these recordings have been increasingly difficult to find of late. But now, here they are, wedded at last to the infinitely more familiar studio sessions, albeit, because of their less favorable sound quality, placed in secondary position on the disc. Besides Miles, the soloists include trombonist Mike Zwerin (later a well-known Europe-based jazz writer), Lee Konitz, Gerry Mulligan, and others from the Capitol dates, but the important thing is that, however small and necessarily repetitious the band’s book of charts, the live performances generally afford greater length of opened-up solo space and an ambience that is considerably “hotter” than in the studio. In addition to reprinting the notes by Pete Welding and Mulligan that accompanied the first Capitol CD (Birth of the Cool, CDP 92862), this set’s booklet also has firsthand reminiscences by Mike Zwerin and Phil Schaap, who has a different theory as to the origin of the airchecks.