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 the Texas revolution. 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. Almonte's journal, lost at the Battle of San Jacinto, which is also presented here with full annotation. His role in the 1836 campaign is examined, as well as his subsequent activities that relate to Texas.