What is the soul? How does it develop? How does it relate to the body? With his unique multi-disciplinary approach, Mulla Sadra approaches these timeless questions through the lens of his transcendental mystical Islamic philosophy. Psychosomatic diseases, life after death, metempsychosis, and the reality beyond this world are all explored here. Spiritual Psychology is a translation of Volumes VIII and IX of Mulla Sadras monumental work al-Asfar al-Arbaah (The Four Spiritual Journeys). Studied in depth in many seminaries, al-Asfar al-Arbaah is a pivotal work in Islamic philosophy and a fascinating excursion into the depths of the divine reality and the human soul. One of the greatest philosophers in Islamic history, Mulla Sadra (1571-1640) founded the transcendental school of philosophy (al-hikmat al-mutaaliyah). Born in Shiraz, Iran, he taught philosophy for many years under the auspices of the Safavid government before retiring to the village of Kahak for a fifteen year retreat. During this time, he formulated his signature approach to philosophy, theology, hadith, and Quranic exegesis an approach which remains influential to the present day.