This article analyzes the origins and development of the dependency theory through the life and work of Theotonio Dos Santos. His formative years at the academy and his early political activism in Brazil are examined, particularly, his time at the University of Brasilia with Vania Bambirra, Ruy Mauro Marini and André Gunder Frank ("the quartet"). This is followed by a discussion about their years of exile in Chile where the quartet regrouped at the Center for Socio-Economic Studies (ceso) of the University of Chile, and where they wrote their founding texts on dependency theory. Chile provided fertile ground for the development of this theory due to its intellectual climate, institutionality, and the country's political transformations in the late 1960s and early 1970s. The military overthrow of the Allende government on that fateful September 11th, 1973 forced the quartet once again into exile. The article continues with an analysis of Dos Santos' writings during his exile in Mexico and then back in Brazil. During this period he became involved with world system theory which culminated in the publication of his extensive trilogy on the contemporary crisis of capitalism and social theory.