This second volume of Gunther Schuller's comprehensive history of jazz covers the period from the 1930s to the late 1940s, decades which saw the transition from big band swing to the virtuoso bop style. The first half of the book concentrates on the band leaders, singers, and composers who dominated the popular music of their day: the jazz aristocracy of Ellington, Basie, and Goodman, as well as major soloists such as Billie Holliday, Art Tatum, Coleman Hawkins, and
Lester Young.

The second half focuses on the origins and early development of bop, the major jazz form of the 1940s, and its two great exponents, Charlie Parker and Dizzy Gillespie.