Duke Ellington called it a barometer of freedom; Nina Simone, a way of life. Ornette Coleman said it was the only music where the same note could be played differently every night; Louis Armstrong said that if you had to ask what it was, you’d never know. Focusing on the traditional side of the sound, here’s a jazz playlist that surveys the greats, past and future. Though much of the material covered here is evergreen, our editors do tweak things now and then, so if you hear something you like, add it to your library.