Jean Dubuffet. Grand Jazz Band (New Orleans), 1944. Image and original data provided by the The Museum of Modern Art. © 2008 Artists Rights Society (ARS), New York / ADAGP, Paris

Happy Jazz Appreciation Month! While the attributes of jazz are difficult to describe without getting technical, the key element that ties together its many sub-genres, from swing to bebop to avant-garde, is improvisation—or as Louis Armstrong put it, “Jazz is music that’s never played the same way once.”