Miguel Centeno wished to share this excerpt from the letter he wrote to nominate Guillermo for the SSRC's Albert Hirschman Prize. I would argue that O’Donnell is the most important Latin American social analyst of the last 40 years. His is not the significance of a theoretical hedgehog such as Cardoso, but of an incredibly insightful fox who brilliantly captured the various eras and paradigms through which Latin America moved during this period. You could argue that if you to had to select one author with which to introduce students to contemporary Latin America, there is no one on O’Donnell’s level; the last few decades of the regions foibles, challenges, and triumphs are all in the pages of his work. I have to admit to a certain bias here, as so much of my career has been shaped by reading his work and seeing the region through his eyes. The first time I encountered O’Donnell was through the very critical eye of Juan Linz (who actually should also be considered for this prize!) Linz didn’t much agree with O’Donnell, but despite all my filial loyalty, I could not help but to appreciate the brilliance of O’Donnell’s insights on Bureaucratic‐Authoritarianism. Partly because of my background, I had been fascinated by the “gangster” models a la Somoza and Batista. By reading O’Donnell, I recognized the shape of the new organizational and institutional animal that had developed in Latin America. What I found even more exciting was that O’Donnell linked these developments to a very specific political and economic context. This was not just another example of an “organizational‐weapon” a la Eastern Europe, but of a very historically contingent interaction between states and societies. Even as many of were grasping what this meant for the region, O’Donnell was unto the next wave. Earlier than most, he recognized that there was a significant structural shift occurring in the 1970s and 1980s which made even these more modernized forms of authoritarian rule untenable. He might not want the credit given some of the silliness that followed, but O’Donnell is very much one of the parents of transitotlogy. His analysis, however, never got bogged down in the search for theoretical universals. He simultaneously respected the specific empirics of the cases, while looking for regular patterns that might give us more comparative lessons. As in the B‐A case, O’Donnell’s method and exposition was in the best Weberian sociological tradition of keeping the particular and the general in constant flux. Anyone reading a piece by O’Donnell has the same (rare) experience of learning something new about a case or a historical instance, and thinking of a phenomenon in a completely new light. Having explained the new forms of authoritarianism, and having analyzed its decline, O’Donnell next moved to the messy insides of the state. Once again before it became popular to do so, O’Donnell challenged our notions of the Latin American state and taught us to note its fundamental shallowness and fragility. In many ways, this may be O’Donnell’s most lasting legacy: an approach to politics that does not over‐privilege the manner in which decisions are taken, but that also analyzes the extent to which they are enforced. With all three of his major stages of work, O’Donnell has not only produced scholarship of the highest caliber, but he has also done so with the ease and clarity of an expert teacher. He has shaped several generations of students who have not had the pleasure to meet him, not only because he’s brilliant, but because he has always cared more about explaining what is going on than in producing paradigms or acolytes. The organizations with which has been most associated, CEDES and the Kellogg, are well known for their intellectual and ideological openness and inspired by the same dedication to simply get it right and to tell it well. To top it all off, Guillermo (if I may) is a wonderful man. I have heard quite a few accounts of his courage facing Argentinean political thugs. More prosaically, I have also heard wonderful stories of an experienced his personal and professional generosity. He, like Hirschman, is a gentleman in every sense of the word and I think each would be delighted to have this mutual association.