In 1974, Anthony Braxton signed with Arista Records. That a major label would take a chance on one of America’s most avant-garde jazz composers was a surprise to many, but he took full advantage of the resources that had been granted him, following up two albums of knotty but compelling small group music with this sprawling opus. The ensemble included AACM peers like saxophonist Roscoe Mitchell, trumpeter Wadada Leo Smith, and pianist Muhal Richard Abrams, as well as synth player Richard Teitelbaum, composer Frederic Rzewski on piano and a phalanx of horns — 22 musicians in all. The music is extremely varied, from the Ellington-esque opener, “W-138,” to the abstract, almost ambient soundscapes of “G-10-K” and “O NB-12” to “22-M,” which starts off as a fairly straight-seeming John Philip Sousa-style march before Wadada Leo Smith bursts out of the pack to take a piercing, squalling trumpet solo, as the horns pulse behind him in a manner that nods to Charles Mingus. This is the place to start if you really want to appreciate Anthony Braxton as a composer and arranger.