The rapid increase of semiconductor devices over the last five to ten years has made it essential for circuit designers, whether involved in hogh-speed digital, optoelectronic or microwave circuits, to gain a deeper understanding of the circuit aspects and fundamental behaviour of high-speed semiconductor devices. This book focuses on circuit theory when using high speed semiconductor devices. It gives a comprehensive introduction suitable for advanced students of electrical engineering and physics. The book is practically orientated, covering not just the physical limits but also technical feasibility. Illustrated, and featuring worked examples throughout, plus extensive exercises with full solutions used to give practical insight and to extend the treatment of the text, this book should be of interest to students and engineers in high speed circuit design, and especially to final year undergraduates and graduate students.