Reséndez is a Mexican historian working at the University of California, Davis. Prior to earning his Ph.D. in history from the University of Chicago, he briefly went into politics and served as a consultant for historical soap operas in Mexico City. He specializes in early European exploration and colonization of the North American continent, the US-Mexico border region, and the early history of the Pacific, especially the voyages of discovery and resulting biological corridor creation. Reséndez has written several books and published numerous articles. The Other Slavery won the 2017 Bancroft Prize honoring outstanding writing in American history and was a finalist for the National Book Award.

Calhoun, like many westbound American settlers, was unaccustomed to Indigenous slavery. Growing up in the American South, he divided his time between managing a successful shipping company in Georgia and pursuing state politics. Reséndez describes Calhoun “as a Georgian [who] had lived his life surrounded by black slaves” (245). He was appointed the first Indian agent for New Mexico in 1849. Within his first six months in New Mexico, he became deeply acquainted with the other slavery, having participated in a peace treaty mission between the New Mexican governor and a group of Navajos.