Think clearly, be sincere, act calmly: Adolf Kussmaul (February 22, 1822-May 28, 1902) and his relevance to medicine in the 21st century.

This past year, 2002, marked the 100th anniversary of the death of Adolf Kussmaul. To rheumatologists, he is important as the author of the first case of idiopathic vasculitis, polyarteritis nodosa, which even today is the basis of our understanding of vasculitis. To general internists, his name is linked to Kussmaul's sign and Kussmaul breathing, and to gastroenterologists, he is in many ways-through the development of the gastric pump and the first gastroscope-the father of modern gastroenterology. His reputation as an excellent teacher, his compassion for his patients, and his ability as a clinician scientist led him to be regarded as a giant of 19th century medicine. Kussmaul's life and career, dedicated foremost to reducing human suffering and advancing medicine as a scientific discipline with a strong humanistic foundation, make him a role model for physicians of today.