The article introduces one of the most prominent scholars of the Shafi‘i school, Imam Ibn Hajar al-Haytami (1503–1566) and his book al-I‘ab Sharh al-‘Ubab. The article also covers the most important aspects of the book and the author's methodology in writing it. The book is one of Imam Ibn Hajar's best works and is notable for its detailed presentation of the scholarly topics and controversies and for the fact that the author analyses and clarifies as well as criticizes and provides counterarguments. This is a commentary (sharh) on Safi al-Din al-Muzajjad's (1443–1523) book «al-‘Ubab al-muhit bi mu‘zam nusus al-Shafi‘i wa al-ashab». The article reflects the main features of the author's methodology, such as: linguistic analysis, detailed analysis and criticism of arguments, the author's position in determination of the preferred opinion in the madhhab. The topic reveals the importance of the scientific and theological edition and publication of the book «al-I‘ab Sharh al-‘Ubab».