The first full-fledged critical edition and historical study of the Erdeni Tunumal Sudur, the Mongolian history of Altan Khan and his descendants, offering a full-range English-written historical and literary evaluation of this unique and fairly reliable, but long neglected discovery in Mongolian studies. With transcription, word index and English translation, as well as extensive commentary on the historical events of Altan Khan’s reign, especially the 1550 attack on Beijing, the 1571 peace accord with the Ming, and the 1578 meeting with the Dalai Lama and the subsequent Buddhist conversion. In particular, the author shows how Altan Khan’s reformulation of the boundaries of Dayan Khan’s Mongol nation and state catalyzed the political fragmentation of the Mongols with dire consequences in relation to the rising Manchu state. Vital for a better understanding of Mongol history during the late Ming.