The saxophonist's first appearances showed his mastery of hard bop, but when he played in Thelonious Monk's late-'50s ensemble his imagination expanded to fit the pianist's example. You can hear Coltrane stretching out during a 1957 take of “Well, You Needn't,” and in no time he put that smoking energy into sessions with Sonny Clark (“Speak Low”) and Red Garland (“Billie's Bounce”).