al-Ghazālī
Iḥyāʾ ʿUlūm al-Dīn — "The Revival of the Religious Sciences." Al-Ghazālī's monumental systematic treatment of Sunni orthopraxy and Sufi ethics (~1100 CE). 40 "books" organised into four quarters: Acts of Worship, Norms of Daily Life, Destructive Vices, and Saving Virtues.
Volume 1
Rubʿ al-ʿIbādāt · Acts of Worship
Knowledge, foundations of belief, ritual purity, prayer, zakāt, fasting, pilgrimage, Quran recitation, dhikr.
Volume 2
Rubʿ al-ʿĀdāt · Norms of Daily Life
Eating, marriage, earning a living, the lawful and the prohibited, companionship, seclusion, travel, music, enjoining good.
Volume 3
Rubʿ al-Muhlikāt · Destructive Vices
The heart, disciplining the soul, gluttony, lust, the tongue, anger, rancour, envy, love of the world, love of wealth, love of rank, ostentation, pride, vanity, self-delusion.
Volume 4
Rubʿ al-Munjiyāt · Saving Virtues
Repentance, patience and gratitude, hope and fear, poverty and renunciation, tawḥīd and tawakkul, love, intention, contemplation, the remembrance of death.
Why the Iḥyāʾ matters to this project
Al-Ghazālī's Iḥyāʾ is the classical synthesis of what Sunni Islam has historically taught its practitioners about conduct, piety, and the heart. Where the Iḥyāʾ assumes a claim as settled (the proper prayer of a menstruating woman, the permissibility of slavery, the spiritual status of music, the treatment of dhimmī, the ethics of jihad, the Sufi reading of particular hadiths), we get an authoritative witness to what "mainstream Islam" has meant in practice — not merely what this or that modern apologist claims. That makes the Iḥyāʾ a useful reference when catalog entries push back on the "not real Islam" defence.