The 4th section of the work  "Interpretation of the "Sources of Questions and Answers" by al-Hakim al-Jishami is the most important monument of medieval Arab-Muslim thought and the largest encyclopedia of classical qalam written by Zaid al-Hakim al-Jishami. The fourth section of this work entitled "Discourse on the Subtle [Matters]," which was written in 'Arabic, opens the sub-series "Primary Sources" — a part of the series "Philosophical Thought in the Islamic World" by the RAS Institute of Philosophy and the Ibn Sina Foundation.

This work containing an introductory research by the publisher provides a detailed account of the natural philosophy, epistemology and anthropology of mu'takalims of Basra and Baghdad and would be of interest to experts in Arab studies, philosophers, and anyone interested in the Eastern intellectual history.

The text, introduction, commentaries and indexes have been prepared by F.O. Nofal, research associate of the Department of Philosophy of Muslim countries.