As is so often true of U.S. perceptions of Latin America, the really big story of the past decade -- the end of seven decades of rule by Mexico's aptly named Institutional Revolutionary Party (PRI) -- passed virtually unnoticed. Preston and Dillon, star "New York Times" reporters and long-time Mexico-watchers, set out to remedy this deficiency, and they succeed brilliantly. The July 2000 election of Vicente Fox brought 71 years of dictatorial rule to a peaceful end, a singular democratic transition that this remarkable book describes in painteresque style. The brisk narrative, full of shrewd analysis and masterly old-fashioned reporting, takes the reader inside the black box of PRI politics, penetrating the circle of powerbrokers as few outside observers ever have to reveal the unspoken rules that kept the party in power and the entrails of the regime as it unraveled. It covers the bitter quarrels between President Carlos Salinas and his successor, Ernesto Zedillo, and the 1994 peso crisis, but Preston and Dillon do not attribute Mexico's democratic transition only to the actions of powerful politicians. There was no single charismatic leader such as Nelson Mandela, no defining dramatic moment such as the fall of the Berlin Wall, no victory by the left or the right, no profound economic transformation. Mexico's democratization was a gradual process, explained by the emergence of a diverse civil society, strong leadership on the left and the right, and the resolve of all parties to avoid fanaticism and violence -- a remarkable achievement given Mexico's bloody political history.