Sources have preserved for us the names and descriptions of many of them. Thus, we know firsthand or by hearing about the most important works left by Ibn Tumart. We can categorize our sources for these works into three types: First: The surviving works themselves, which are a collection of books and treatises. Second: Biographies and history, in particular. These are limited to two books: "Muhadhdhi al-Muwat'a" and "Kutub Munarrada". Third: Books and treatises collected in a single volume. This is the volume known as "A'azz ma Yutlab". This collection was surrounded by circumstances that require further explanation and clarification. Many researchers mistakenly believe that the collection called "A'azz ma Yutlab," attributed to the Mahdi, is a single book authored by him. This misconception has become common. It is a collection of various topics and diverse methodologies. This meaning is conveyed by the following phrase at its end: "A volume containing all the pronouncements of the infallible Imam, the known Mahdi." The same page also contains the phrase: "It contains the books: A'azz ma Yutlab, concerning prayer..." These two phrases indicate that it is a collection, not a single book. See a detailed description of these works on page 149 and onwards. See a comprehensive article about it by Yahya Huwaydi, "A'azz ma Yutlab": page 374 and onwards. The last collection of "A'azz ma Yutlab" (unnumbered page). 146