Based on information not available previously, this comprehensive study details the history, evolution, and changing relationship between the armed forces and civilian leadership in Mexico in the second half of the 20th century. Camp focuses on the past two decades during which democratic transformation produced important changes within the armed forces, in particular the navy. Despite institutional autonomy, a lack of reform, and an increase in civilian missions, the Mexican armed forces remain subordinate to civilian political authorities, and Camp finds little evidence to support the common notion that they are a significant threat to civilian supremacy in general or to the democratic process in particular. This work draws from published and unpublished sources, military websites, and material obtained through numerous freedom of information requests made directly through the secretariat of national defense. It includes correspondence and interviews with Mexican officers, specialists and journalists who have covered the military and American officers who have trained or worked with the Mexican armed forces. Based upon thirty-five years of research, Camp incorporates detailed data on 670 army, air force, and naval officers at the two or three star rank, into the only comprehensive biographical data bank ever compiled on the Mexican military. This allows for insightful comparisons between the navy and army, on such topics as leadership, training, international education, and promotion. It reveals new organizational developments within the armed forces, especially the navy, and the new roles civil political institutions are playing vis-a-vis the armed forces.