When Miles Davis’ funk became increasingly dense, his onetime bandmates Joe Zawinul and Wayne Shorter pared things back in their new group, yet never lost that vital sense of groove. The opening cuts here court the pop market; it’s easy to imagine a young Prince digging "American Tango." But the instrumentalists' chops are on full display, as with Shorter’s soprano solo on the funky "Cucumber Slumber." By pushing deeper into electric instrumentation without losing their feel for song, this fusion ensemble created a jazz-funk masterpiece.