Kashf aẓ-Ẓunūn ‘an 'asāmī ‘l-Kutub wa'l-funūn (كشف الظنون عن أسامي الكتب والفنون) (‘Opinion’s Scrutiny of the Names of Books and the Sciences’). Begun in Aleppo in 1042 AH/1632 AD and completed in about 1062 AH/1652 AD, it is a vast bibliographic-biographical dictionary in Arabic, and a research-tool for scholars. Its list, approx. 15,000 Arabic, Persian and Turkish titles, 9500 authors and 300 arts and sciences, comprises the most extensive bibliographical dictionary of Islamic literature. It was published as Lexicon Bibliographicum et Encyclopaedicum in Latin in 7 vols.

When revealing the subtleties of sciences and clarifying their facts for the sake of talents and the dearest of demands, God Almighty in every age arrested scholars who carried out the burdens of that great matter, and revealed the leg of seriousness and interest in education and understanding, especially the prominent imams of the scholars of Islam about whom the Prophet (peace and blessings of God be upon him) said The scholars of my nation are like the prophets of the Children of Israel, for they are a race of ends, legends, narrations and know-how. However, the names of their blogs have not been written down yet, and there is no doubt that telling Al-Ayoun with news of their tracks is the goal and the demand. Therefore, Haji Khalifa Mustafa bin Abdullah wrote his book Kashf al-Dunun, which included the sum of the names of the books, in which he wrote all what he saw by tracing the literature and browsing the books of dates and classes, and made it arranged according to the letters of the lexicon. And make it an introduction, chapters and conclusion. And he made the introduction to the conditions of sciences, in which he spoke about the virtue of knowledge, learning and teaching, about the conditions and functions of a Muslim, the conditions and manners of a teacher, and an explanation of the ratio between the way of looking and the path of purification, and about the sciences related to purification that are the fruit of working with knowledge, and about the inner sciences: worship, habits, destruction and salvation. As for the four chapters, they included the names of the books found in Al-Azhar and other schools of interpretation, renewal, readings, and what is related to the Qur’an. It includes the names of hadith books, hadith explanations, hadith terminology, and other matters related to the hadiths of the Prophet. It also includes what is related to the principles and what it includes, jurisprudence, texts of jurisprudence, and explanation of jurisprudence. On the doctrines and includes the science of mysticism, preaching, histories, medicine, grammar, explainers of all, Persian letters, messages on meanings and eloquence, and the entirety of science related to each of its arts.