"Imam Hassan al-Askari (A.S)" by Sheikh al-Mufid provides an in-depth account of the life and contributions of Imam Hassan al-Askari (A.S), the eleventh Imam in Twelver Shia Islam. The book delves into the historical and theological aspects of his life, focusing on his role in the Shiite tradition, his experiences, and the challenges he faced. It highlights his contributions to Islamic teachings and his significance in the lineage of the Imams leading up to Imam Mahdi (A.S).