A millennium after his life, Avicenna remains one of the most highly regarded physicians of all time. His Canon of Medicine, also known as the Qanun, is one of the most famous and influential books in the history of medicine, forming the basis for our modern understanding of human health and disease. It focused not simply on the treatment of symptoms, but on finding the cause of illness through humoral diagnosis-a method still used in traditional Unani and Ayurvedic medicines in India. Originally written in Arabic, Avicenna's Canonwas long ago translated into Latin, Persian, and Urdu, yet many of the inaccuracies from those first translations linger in current English translations. Translated directly from the original Arabic, this volume includes detailed commentary to explain current biomedical interpretations of Avicenna's theories and ways to apply his treatments today, particularly for individualized medicine. It shows how Avicenna's understanding of the humors corresponds directly with the biomedical definition of proteins, lipids, and organic acids: the nutrient building blocks of our blood and body. With this new translation of the first volume of his monumental work, Avicenna's Canonbecomes just as relevant today as it was 1,000 years ago.