Charles H. Harris is the author and co-author of ten books on the Mexican Revolution, the Texas Rangers, and the FBI. These works include The Great Call Up, The Secret War in El Paso, The Texas Rangers and the Mexican Revolution, The Archeologist was a Spy, and The federal Bureau of Investigation before Hoover. A retired professor from the New Mexico State University, Charles Harris specializes in using primary archival sources to produce some of the most cited works in Mexican and border history today.