This book is considered one of the most important Arab bibliographic sources. Its author proved extraordinarily adept at elegantly classifying Arab sciences by topic, based on the concept of gradually progressing from the general to the specific. He excelled in identifying and branching disciplines, identifying well over 320. The author introduced each science, defining its scope of specialty, outlining its principles, benefits and purposes, and indeed, going further to present the origin and historical evolution of many disciplines.