The Improbable Conquest offers translations of a series of little-known letters from the chaotic Spanish conquest of the Rio de la Plata region, uncovering a rich and understudied historical resource. These letters were written by a wide variety of individuals, including clergy, military officers, and the region's first governor, Pedro de Mendoza. There is also an exceptional contribution from Isabel de Guevara, one of the few women involved in the conquest to have recorded her experiences. Writing about the conditions of settlements and expeditions, these individuals vividly...