In late 1833 Mexico began to have serious fears that its northeastern territory in Texas would be lost to North American colonists. To determine the actual state of affairs, Mexico sent Col. Juan N. Almonte to Texas on an inspection--the last conducted by a high-ranking Mexican official before revolution separated Texas from Mexico. Upon his return to the Mexican capital in November 1834, Almonte wrote a secret report of the measures necessary to avoid the loss of Texas--a report that has been unknown to scholars or the general public.Here it is presented in English for the first time, along with more than fifty letters that Almonte wrote during his inspection. This documentation offers crucial new insights on Texas affairs and will change the way historians regard Mexico’s attitudes toward the foreign colonists and their revolution of 1835-1836.When Santa Anna marched an army north to crush the Texas rebellion, Almonte was by his side as a special advisor. He kept a journal, lost at the Battle of San Jacinto, which is presented here with full annotation. Almonte’s role in the 1836 campaign is examined, as well as his subsequent activities that relate to Texas.