Ibn al-Nafis was a 13th-century Arab physician and scholar, best known for his discovery of the pulmonary circulation of blood. He was born in Damascus and later worked in Cairo, where he contributed significantly to medical knowledge. His most famous work, "Commentary on the Anatomy of Avicenna," challenged the ideas of earlier scholars like Galileo and Avicenna. In addition to his work in medicine, Ibn al-Nafis was also a prolific writer in various fields, including philosophy and theology. He emphasized the importance of observation and experimentation in medicine, laying the groundwork for future advancements in the field. His contributions remain influential in both Islamic and Western medicine.