This award-winning study explores the obscure transitional period of Imāmī intellectual history between the decline of the Kūfah school and the rise of the Baghdād school. Dr. Mūsavī Tanyānī tracks how theological legacies migrated and reconfigured across Baghdād, Baṣrah, and Khurāsān. The research reveals the regional dynamics and scholarly networks that eventually synthesized into systematic Shīʿī theology under Shaykh al-Mufīd.