To a large extent, our lives on this earth depend on systems that operate autoΒ matically. Manysuchsystems can be found in nature and others are man made. These systems can be biological, electrical, mechanical, chemical, or ecological, to namejust a few categories. Our human body is full ofsystems whose contiΒ nued automatic operation is vital for our existence. On a daily basis we come in contact with man made systems whose automatic operation ensures increaΒ sed productivity, promotes economic development and improves the quality of life. A primary component that is responsible for the automatic operation of a system is a device or mechanism called the controller. In man made systems one must first design and then implement such a controller either as a piece of hardware or as software code in a computer. The safe and efficient automatic operation of such systems is testimony to the success of control theorists and practitioners over the years. This book presents new methods {or controller design. The process ofdeveloping a controller or control strategy can be dramatically improved if one can generate an appropriate dynamic model for the system under consideration. Robust control design deals with the question of how to develop such controllers for system models with uncertainty. In many cases dynamic models can be expressed in terms oflinear, time invariant differential equations or transfer functions.