not prove to be as popular as his medical encyclopedia in the Islamic circles, the book is of great interest today specially for science historians who are mostly concerned with its celebrated discovery of the pulmonary circulation. The book discusses the anatomical concepts of Avicenna's Canon. It starts with a preface in which Ibn al-Nafis talks about the importance of the anatomical knowledge for the physician, and the vital relationship between anatomy and physiology. He then proceeds to discuss the anatomy of the body which he divides into two types; the general anatomy which is the anatomy of the bones, muscles, nerves, veins and arteries; and special anatomy which is concerned with the internal parts of the body like the heart and lungs. What distinguish the book most is the confident language which Ibn al-Nafis shows throughout the text and his boldness to challenge the most established medical authorities of the time like Galen and Avicenna. Ibn al-Nafis, thus, was one of the few medieval physicians—if not the only one—who contributed noticeably to the science of physiology and tried to push it beyond the hatch of the Greco-Roman tradition. Commentary on Hippocrates' "Nature of Man" The particular manuscript of Ibn al-Nafis' commentary on Hippocrates' Nature of Man is preserved by the National Library of Medicine. It is unique and significant because it is the only recorded copy that contains the commentary from Ibn al-Nafïs on the Hippocratic treatise on the Nature of Man. Al-Nafïs's commentary on the Nature of Man is found in Sharh Tabi'at al-Insan li-Burqrat. It offers an idea of medical education during this period, in the form of an ijaza included with the text. This document reveals that Ibn al-Nafïs had a student named of Shams al-Dawlah Abü al-Fadi ibn Abï al-Hasan al-Masïhï, who successfully read and mastered a reading course associated with the treatise, after which al-Masïhï received this license from Ibn al-Nafïs. Based on evidence from commentaries such as this one, modern scholars know that physicians in this era received a license when they completed a particular part of their training. Commentary on "Endemics" In the second half of the thirteenth century, Ibn al-Nafïs composed the first Arabic commentary on Hippocrates' Endemics. The commentary is lengthy and contains two extant manuscripts, made up of 200 and 192 folios. Ibn al-Nafïs’ commentary on Hippocrates’ Endemics in Sharh Abidhimya li-Burqrat is an analysis of Hippocrates three constitutions.