Abu al-Hasan al-Razi, also known as Al-Razi, was a prominent Persian physician and philosopher who lived during the Islamic Golden Age, around the 9th to 10th centuries. He is best known for his contributions to medicine, particularly his influential medical encyclopedia, the Kitab al-Hawi, which compiled knowledge from various sources and included his own observations. In addition to his medical work, Al-Razi made significant advancements in chemistry and is often regarded as one of the early pioneers of the field. He was also known for his writings on philosophy and ethics, which contributed to the intellectual discourse of his time and influenced later scholars, including Ibn Sina.