This is Book 12 of Ihya 'Ulum ad-Din, the Imam's most famous work. In it are covered every aspect of the institution of marriage. In the words of Imam Ghazali, "Marriage comes to religion's aid, striking devils with dismay. How appropriate that one should study its occasions, preserve its sacred traditions and its etiquette, explain its aims and purposes, and detail the paragraphs and chapters of the subject. Its most important precepts will be expounded in three chapters:
1) The pros and cons of marriage;
2) The proprieties to be observed in respect of the contract and the two contracting parties;
3) The right conduct of conjugal life from the time of the contract until separation occurs."
Translated by Muhtar Holland.