During the eighteenth century the Bajio emerged from its frontier condition to become the pace-maker of the Mexican economy. Silver mining boomed and population increased rapidly. It is the aim of this book to examine the impact of these dramatic changes on the structure of agricultural production and the pattern of rural society. In his Miners and Merchants in Bourbon Mexico 1763–1810 (Cambridge Latin American Studies 10) Dr Grading demonstrated how the local entrepreneurial elite accumulated vast fortunes during the mining bonanza at Guanajuato. In this present work he describes how many of the same men invested their capital in the purchase and improvement of haciendas in the nearby district of Leon. The countryside was transformed as wasteland was cleared for ploughing, or was irrigated.