Book excerpt: The Mexican Revolution (1910-19) was the first seismic social convulsion of the twentieth century, superseded in historical importance only by the Russian and Chinese revolutions. Tierra y Libertad (land and liberty) was the watchword of the revolutionaries who fought a succession of autocrats in Mexico City. But the revolution was fired by a confusing multiplicity of issues- local, national, international, cultural, racial and economic. The two greatest rebel leaders were Francisco (Pancho) Villa and Emiliano Zapata, and Frank McLynn here tells the story of the Revolution through a dual biography of these legendary heroes.The great ten-year struggle that devastated Mexico was essentially a war on two fronts- in the north waged by Villa and a mobile army of ex-cowboys and ranchers; and in the south carried on by Zapata and an infantry army recruited from the peons of the sugar plantations. Villa was the Revolution's great military hero, but Zapata was its soul and the only rebel whose revolt was aimed at a genuine root-and-branch transformation of Mexican society. The two men reached the peak of their careers in 1914 when they met briefly in triumph in Mexico City. Failing to make common cause, over the next five years they gradually fell victim to their great rivals.