Outwardly, Miles in the Sky is another in a series of brilliant studio albums by Miles Davis’ famed second quintet. But changes were afoot: “Stuff,” the opening Davis original, found Herbie Hancock on electric piano and Ron Carter on electric bass. On Wayne Shorter’s “Paraphernalia” they both returned to acoustic instruments, but guitarist George Benson slipped into the lineup, playing a funky ostinato and contributing a fluid solo. Joe Beck was also a guitarist recording with Miles around this time—another harbinger of Davis’ full-fledged electric period, which began when John McLaughlin entered the picture on In a Silent Way and Bitches Brew. Miles in the Sky is therefore a transitional record, not unlike Filles de Kilimanjaro, recorded very soon after. Miles in the Sky is also the last intact second quintet album. (Filles included tracks with Hancock and Carter but also others with Chick Corea and Dave Holland.) There are just four tracks, rather long ones, capturing some of the open, extended improvisational energy the band was known for in live settings. Drummer Tony Williams thrived on that energy in particular, and his performances on Miles in the Sky, not least on his own “Black Comedy,” are ceaselessly creative and explosive. Davis, too, brings exceptional power and clarity of tone; his closing “Country Son,” a curious hybrid of swing, funk, and dreamy drone ballad episodes, sets Hancock up for some extraordinary soloing (on the alternate take perhaps even more so).