Emilio Kosterlitzky (1853-1928) was born in Moscow, Russia and attended military school. In 1872, he abandoned his training and headed to Mexico, where he enlisted as a private in the Federales. Kosterlitzky served as an officer for the Mexican Army from 1873 to 1914, reaching the rank of colonel by 1912, and as a Special Agent for the U.S. Department of Justice from 1915 to 1927. He was an enthusiastic supporter of Mexican President Porfírio Diaz (1884-1910) in his efforts to improve the country's economy through foreign investment.
The collection contains correspondence, photographs, biographical materials, clippings, official commissions and citations, chiefly concerning his service record and military activities. Correspondents include Porfírio Díaz, Leonard Wood, and Harrison Gray Otis. Also includes correspondence of Ernest Kosterlitsky concerning a projected book about his father Some materials in this collection are reprinted in Emilio Kosterlitsky: Eagle of Sonora and the Southwest Border by Cornelius C. Smith Jr., published by Arthur H. Clark Co, in 1970.