Since its publication in 1950, Alan Lomax's book Mr. Jelly Roll: The Fortunes of Jelly Roll Morton, New Orleans Creole and "Inventor of Jazz" has been a crucial source for jazz music scholars. Based on Lomax's 1926 interviews of Morton for the Library of Congress, the book presents a compelling and colorful portrait of the pioneering jazz pianist and the early days of New Orleans jazz. In 2005, Rounder Records released these recorded interviews, complete, for the first time, along with transcripts, notes, and other useful supplemental materials. By comparing this new information with Lomax's book, this paper examines the ways Lomax imposed his own agenda on Mr. Jelly Roll, departing significantly from Morton's own testimony. Motivated by his convictions about authenticity, jazz music, and the commercial recording industry, Lomax created a biased and sometimes inaccurate profile of Morton that has influenced public opinion and scholarship to this day.