Ibn al-Nafis (1210–1288 CE), also known as Ala-al-din Abu al-Hasan Ali ibn Abi-Hazm al-Qarshi al-Dimashqi, was a renowned Arab physician, theologian, and polymath from Damascus, Syria. He is best known for his groundbreaking work in medicine, particularly his pioneering understanding of pulmonary circulation. Ibn al-Nafis challenged the prevailing theories of his time, including those of Galen, by proposing a more accurate model of blood circulation through the lungs. His work, "Al-Shamil fi al-Tibb" (The Comprehensive Book on Medicine), became a significant medical textbook in the Islamic world. Ibn al-Nafis's contributions to medicine and science have had a lasting impact, and he is considered one of the most important figures in the history of medicine.