This study is concerned with the day-to-day government of a remote Spanish American province at the time when the disorders of conquest were giving way to a settled administration. Most of the material was collected in the course of visits to Mexico and Spain before the recent war. The first five chapters were written in 1939. The work had then to be laid aside, and did not emerge from its drawer until the beginning of 1946. Belated but none the less sincere thanks are due to Mr F. A. Kirkpatrick; to the distinguished historian of New Galicia, Sr. J. López-Portillo y Weber; and to Sr. J. de la Peña, of the Archive of the Indies in Seville. Especially I would wish to thank Professor C. H. Haring for his teaching and encouragement during a most happy year at Harvard before the war, and for his kindness in reading the manuscript since its completion.