This book introduces magnetic bearings—mechatronic devices that produce contact-free electromagnetic force to support a load, such as a moving train or a spinning rotor. Compared to traditional bearings, magnetic bearings offer several advantages: no friction, low heat generation, no required lubrication, quiet operation, and fast and stable rotation. For these reasons, magnetic bearings have been used in rotary ventricular assist devices (VADs) to increase design life, reduce or eliminate material wear and bearing maintenance, as well as to increase biocompatibility by eliminating high fluid stresses and heat generation, both of which are associated with hemolysis, platelet activation and aggregation, and thrombus growth. The book covers the principles of these bearings, how they are used in integrated control and electronics systems, and useful information on several major brands of current assist devices.