He is a member of the Comprehensive Cancer Center, and is a surgical consultant at the Ann Arbor Veterans Administration Medical Center. Dr. Knol received his bachelors degree at Calvin College in Grand Rapids, Michigan, and received his M.D. degree from the University of Michigan Medical School in 1974. He completed a General Surgery residency at the University of Michigan in 1980. He has been on the Surgery faculty at the University of Michigan since 1980. He is Board Certified in General Surgery. Dr. Knol's clinical practice is gastrointestinal surgery which includes all aspects of surgical care for the stomach, small intestine, colon, rectum, anus, liver, gallbladder, bile ducts, and pancreas, including diagnostic endoscopy and laparoscopic surgery. He also performs surgery for portal hypertension.