Guillermo A. O'Donnell (1936–2011) was a prominent Argentine political scientist, who spent most of his career working in Argentina and the United States, and who made lasting contributions to theorizing on authoritarianism and democratization, democracy and the state, and the politics of Latin America. His brother, Pacho O'Donnell, is a well-known politician and writer.

Professor Philippe C. Schmitter was Professor of Political Science at the European University Institute in Florence, Department of Political and Social Sciences until September 2004. He was then nominated Professorial Fellow at the same Institution. He is now Emeritus of the Department of Political and Social Sciences at the Europena Univeristy Institute.

aurence Whitehead is Official Fellow in Politics at Nuffield and Director of the Mexican Studies Programme. Among his special interests are US relations and European relations with Latin America and current processes of democratisation. He is the representative on the steering committee of the newly created Red Euro-Latinoamericano de Gobernabilidad par el Desarrollo, which is supported by the IDB and holds an annual conference in Barcelona. He is also Chair of the Europe-Latin American section of LASA and of Research Committee 13 (on Comparative Democratization) at IPSA. In that capacity he gave a keynote address to the annual conference of the Brazilian Association of Political Sciences in Rio (July 2004). In 2002 he occupied the Alfonso Reyes Visiting Professorship at the Institut des Hautes Etudes d'Amerique Latine in Paris. He also teaches the options on Mexican politics, the international relations of Latin America, and on comparative social revolutions at the Centre. His most recent publications are Democratization: Theory and Experience (Oxford University Press, 2002) and an edited volume Emerging Market Democracies: East Asia and Latin America (Johns Hopkins University Press, 2002). Other publications include Toward Democratic Viability: the Bolivian Experience (Jointly edited with John Crabtree, Palgrave, 2001); International Dimensions of Democratisation (OUP 1996, enlarged paperback edition, 2001), two chapters for the Cambridge History of Latin America (on 'the development of state organisation since 1930', and on Bolivia since 1930) and a series of articles and chapters on various aspects of democratisation. Earlier publications include Transitions from Authoritarian Rule (jointly edited with Guillermo O'Donnell and Philippe Schmitter - Johns Hopkins University Press); Latin America Debt and the Adjustment Crisis (jointly edited with Rosemary Thorp, Macmillan); and The Central American Impasse (jointly edited with Giuseppe di Palma - Croom Helm). He has also written various articles about Bolivia and about Chile since Allende. He is editor of the OUP book series 'Oxford Studies in Democratisation'. He was Acting Program Director at the Center for US-Mexico Studies of the University of California, San Diego, in 1985-6 and co-ordinator of the Southern California workshop on Political and Economic Liberalisation in 1995. - See more at: http://www.lac.ox.ac.uk/laurence-whitehead#sthash.GCyDlqR5.dpuf

Political science scholars consider the four-volume work Transitions from Authoritarian Rule to be a foundational text for studying the process of democratization, specifically in those cases where an authoritarian regime is giving way to some form of democratic government. The most important of the four books is without a doubt the fourth volume, Tentative Conclusions about Uncertain Democracies, also known as "the little green book."

Transitions from Authoritarian Rule was the first book in any language to systematically compare the process of transition from authoritarianism across a broad range of countries. Political democracy is not the only possible outcome. Guillermo O’Donnell, Philippe C. Schmitter, and Laurence Whitehead emphasize that it's not the revolution but the transition that is critical to the growth of a democratic state. This ground-breaking insight remains highly relevant as the ramifications of the Arab Spring continue to play out.