Sharh Taqdimat-il-Ma'rifah (Commentary on the Introduction of Knowledge) by the leading Arab physician known as al-Dakhwar (Damascus, ca. 565/1170 - 620/1230). (Abd al-Rahman ibn Ali al-Dakhwar). He served Ayyubid rulers and was chief medical oficer of his time. He was an educator of prominent physicians, including Ibn Nafis who discovered blood circulation in the body.