Recent publications about King Alfonso X have tended to focus on his role as monarch in the context of the institutions of the realm. This book, however, emphasizes the human dimension of this extraordinary figure. Drawing on King Alfonso’s own works and on extensive archival sources, both well-known and neglected, Salvador Martínez brings to life a king who valued the possession of knowledge above all earthly riches. The "Learned King" left a vast legacy of work, which would influence developments in both Spain and Europe, most significantly in the transfer of knowledge from the Arabs to the Christian West. With his intellectual curiosity and his pursuit of wisdom, Alfonso X is a towering figure at the origins of modernity.