Sufism, or Islamic mysticism, is concerned with direct personal experience of and communion with God through subjective experience. Early Sufis sought to devote themselves to spirituality and moved away from politicized cities. Key Sufi practices included asceticism, prayer, recitation of the Quran, and contemplation. Sufism is primarily learned through serving a teacher for many years. Central Sufi doctrines include the unity of all phenomena as manifestations of a single divine reality, and the concept of the "Perfect Man" who acts as a channel of God's grace. The goal of Sufism is realization of the divine unity by letting go of notions of duality and the individual self