Book excerpt: Now with a new introduction by David Rieff, "The Lawless Roads" is the result of Graham Greenes expedition to Mexico in the late 1930s to report on how the inhabitants had reacted to the brutal anticlerical purges of President Calles. His journey took him through the tropical states of Chiapas and Tabasco, places where all the churches had been destroyed or closed and the priests driven out or shot. The experience provided Greene with the setting and theme for one of his greatest novels, "The Power and the Glory,"