People who pursue careers in Internal Medicine are drawn to the specialty by a love of patients, mechanisms, discovery, education, and therapeutics. We love hearing the stories told to us by our patients, linking signs and symptoms to pathophysiology, solving the diagnostic dilemmas, and proposing strategies to prevent and treat illness. It is not surprising given these tendencies that internists prefer to continue their life-long learning through problem solving. This book is offered as a companion to the remarkable 17th edition of Harrison’s Principles of Internal Medicine. It is designed for the student of medicine to reinforce the knowledge contained in the parent book in an active, rather than passive, format. This.