Based on newly available archival records, this article examines the life and thought of Andre Gunder Frank from his years as a graduate student in development economics to the publication of his first and most influential book. A closer look at the evolution of Frank's thought provides new insight into the relationship of his brand of “neo-Marxist” development theories with both classical Marxism and modernization theory. Frank interpreted Marxist political debates according to the categories of thought of 1950s American development economics, and in doing so he both misinterpreted fundamental aspects of Marxism and simultaneously generated lively theoretical debates that remain relevant today.