Like few jazzmen of his age and eminence, Ellington not only regularly collaborated with hot young players during the post-bop era, he consistently met them — challenged them — on their own turf. The premiere example is this date, where three kings — Charles Mingus on bass, Max Roach on drums, each at the height of his preeminence — became, in promoter George Wein’s words, “a triumvirate, not a trio.” As critic Ben Ratliff put it, “The music has its feelings on the surface.” The title track comes on so rambunctious it can be easy to recall the whole session as being equally spiky, but not all of it was: this version of “Warm Valley” is strikingly pacific.