After "Invisible Man" published in 1952, Ralph Ellison started work on his second, "Juneteenth," in 1954. Ellison's literary executor John F. Callahan cobbled 2,000 pages of his writings and published that second novel posthumously in what year?

After "Invisible Man" published in 1952, Ralph Ellison started work on his second, "Juneteenth," in 1954. Ellison's literary executor John F. Callahan cobbled 2,000 pages of his writings and published that second novel posthumously in what year?