The masterpiece of Imam al-Ghazali, unquestionably one of the greatest thinkers and theologians of Islam. He reflects on the totality of his studies in Tasawwuf (Sufism) and its related components (purification of the heart, soul, mind and body), tazkiyya, scepticism, philosophy, and spiritual retreat.
This work, known in English as "Revival of the Religious Sciences."
Volume 1 - Book of Worship
Volume 2 - Book of Worldly Usages
Volume 3 - Book of Destructive Evils
Volume 4 - Book of Constructive Virtues.
English translation by Maulana Fazlul Karim.