Those who pine for a new “big idea” in jazz—one that lends the music’s next chapter a catchy name—miss what’s going on. Radical thinkers—seeming outliers—are today’s prime movers. If this has been the case throughout much of jazz’s history, what is different today is that such innovators no longer beget clear schools that gain popularity, such as bebop or even free jazz. Jazz’s forward flow is not well measured by stylistic monikers and pop-culture breakthroughs, but rather through profound ripples of impact. The most influential musicians now suggest less about how jazz should sound or be sold and more about how meaningful musical possibilities may be awakened within the context of jazz tradition. On those terms, two musicians— Henry Threadgill, 71 years old, and Steve Coleman, 58—loom especially large.