Richard Fletcher's biography of El Cid investigates the life and legend of the famed Castilian nobleman Rodrigo Díaz de Vivar. Drawing on primary sources and historical analysis, Fletcher aims to separate the historical figure from the mythic hero that has been perpetuated through centuries of literature and folklore.

Richard Fletcher's work is recognized for its rigorous scholarship in disentangling the historical El Cid from his romanticized image. Scholars often cite Fletcher's ability to navigate the sparse and often contradictory primary sources to present a nuanced portrait of the medieval warrior. The book is considered a significant contribution to the understanding of both El Cid and the complex dynamics of medieval Spain.