Political science scholars consider the four-volume work 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, , also known as "the little green book." 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. This reissue features a new foreword by Cynthia J. Arnson, director of the Latin American Program at the Woodow Wilson International Center for Scholars, and Abraham F. Lowenthal, founding director of the Latin American Program, who wrote the original volume's foreword.