The second album by Miles Davis’ Second Great Quintet found the group settling into its aesthetic—freer rhythmically than other hard-bop units, but still rooted in tunes. And what tunes: Here’s the recording that made saxophonist Wayne Shorter’s “Footprints” into a standard. (Ditto for “Orbits.”) Limit-pushing is the order of the day: Herbie Hancock plays with just his right hand on select cuts. Drummer Tony Williams daringly switches meters. And Miles is Miles, his burnished sound well justifying the album cover’s satisfied mien.