William Osler (1849-1919) was generally regarded as the greatest and most respected physician of his time. He is still considered by many in these terms. Others have questioned the relevance of Osler's teachings in recent years. This paper describes Osler's life and gives his philosophy and views in his own words. An outstanding clinician who emphasized bedside teaching and observation, he possessed extraordinary charm that inspired many disciples. As Professor of Medicine at 4 institutions in 3 countries, he exerted a profound influence on medical education. He was a prolific writer and his textbook became the most popular and widely read treatise on medicine in the world. He also was a medical historian, a classical scholar, and an avid bibliophile. He emphasized the value of hard work and ongoing education. His comparison and concern for patients and colleagues reflected his personality. Osler's wisdom is as relevant now as in his era. It is likely that he would be in the forefront of medical science if he were alive today. Osler blended the art and science of medicine perhaps better than anyone else and remains a valuable role model for students and physicians more than 75 years after his death.