From the Acoustic Sounds website: "The motor on the studio's 3-track master recorder was running slowly the day of the album's first session. This speed issue affected the album's first three tracks, "So What," "Freddie Freeloader" and "Blue in Green," making them a barely perceptible quarter-tone sharp. Before now, it was only addressed in 1995 for the Classic Records edition and by Columbia Records — or their latter-day parent, Sony Music — on a CD reissue in the late '90s. This edition also contains on Side 4 "Flamenco Sketches (alternate take)" cut at 45 RPM." (Sides A-C are 33 1/3 RPM)