The classic lineup was Miles Davis on trumpet, Wayne Shorter on tenor saxophone, Herbie Hancock on piano, Ron Carter on bass, and Tony Williams on drums. Worth pausing on that last name: Tony Williams was seventeen when he joined. Seventeen. He played with a kind of controlled ferocity that pushed the whole band without ever tipping into chaos, and his influence on every drummer who came after him is almost impossible to overstate. The rhythm section of Hancock, Carter, and Williams became a unit unto itself — they called what they did "time, no changes," meaning they could stretch and compress the pulse without ever losing the thread.

What made the quintet sound different from what came before was the way they handled time and structure. They weren't playing free jazz — there were still heads, still chord changes — but they treated those structures as suggestions rather than rules. Herbie Hancock might drop a chord somewhere unexpected. Ron Carter might pull the tempo forward or let it breathe. Miles Davis could play a phrase that implied a completely different harmonic center than what was written, and the band would follow him there and back without blinking. It sounded relaxed even when it was incredibly complex.

The studio records from this period — E.S.P. (1965), Miles Smiles (1966), Nefertiti (1967), Filles de Kilimanjaro (1968) — hold up in a way that a lot of jazz from that era doesn't. They don't sound dated. Part of that is because the playing is so conversational and attentive that it draws you in regardless of when it was made. Wayne Shorter contributed most of the compositions, and they have an angular, slightly off-kilter quality that gave the band interesting problems to solve every night. Shorter's tunes don't resolve the way you expect them to, which suited this particular group perfectly.

The live recordings, especially the ones that have come out over the years on the Columbia and bootleg circuit, sometimes outpace the studio work. You can hear the band taking bigger risks, Williams pushing harder, Miles sitting back or cutting in at unexpected moments. There's a version of "Agitation" from various live dates that makes the studio take sound almost cautious by comparison. If you want to understand what this group actually felt like in the room, start there.

By 1968, Miles Davis was already pulling toward electric instruments and a different kind of rhythm. Filles de Kilimanjaro has electric piano on some tracks, and you can hear the band starting to flex in a new direction. Within a couple of years, most of the members had moved on to lead their own groups — Herbie Hancock, Wayne Shorter, Tony Williams, and Ron Carter all built substantial careers that went in very different directions. That scattering is probably the best evidence of how much talent was concentrated in one place for those few years.