This multi-disciplinary and inter-disciplinary work presents the rethinking of the entire tradition of Islamic philosophical psychology by Mulla Sadra on the most profound questions and issues pertaining to the soul. It includes the views of the ancient Greek philosophers and physicians, Muslim philosophers, theologians, Sufis, theosophists and physicians, the teachings of the Qur’an, the Traditions of the Prophets and the Shi‘ite Imams, and Mulla Sadra’s own profound insights and intellectual elucidations combined with impeccable logical proofs and demonstration. It deals with the definition of the soul, the proof of its existence, its birth as corporeal and its survival as spiritual, various levels of the soul and the body, the vertical development of the soul through its substantial motion, the soul-body relation, the holistic approach to psychosomatic diseases, the resurrection and post-mortem survival of the soul, the body of the resurrection, his original interpretation of metempsychosis, the meaning of Heaven and Hell and the intellectual or spiritual worlds beyond this world