PHEMT devices and their incorporation into advanced monolithic integrated circuits is the enabling technology for modern microwave/millimeter wave system applications. Although still in its infancy, PHEMT MIMIC technology is already finding applications in both military and commercial systems, including radar, communication and automotive technologies. The successful team in a globally competitive market is one in which the solid-state scientist, circuit designer, system engineer and technical manager are cognizant of those considerations and requirements that influence each other's function. This text provides the reader with a review of PHEMT technology, including materials, fabrication and processing, device physics, CAD tools and modelling, monolithic integrated circuit technology and applications. Readers with a broad range of specialities in one or more of the areas of materials, processing, device physics, circuit design, system design and marketing are introduced to important basic concepts and techniques. The specialist who has specific PHEMT experience should benefit from the broad range of topics covered and the open discussion of practical issues.