This Transactions issue is a first in joint sponsorship within the IEEE. It involved the coordinated publication efforts of the IEEE TRANSACTIONS ON ELECTRON DEVICES, the IEEE JOURNAL OF SOLID-STATE CIRCUITS, and the IEEE Transactions on Microwave Theory and Techniques. The involvement of three distinct publications demonstrates the wide interest of the technical community in this new and challenging field of microwave integrated circuits. I t also shows the accelerated evolution of a technology when broad and varied disciplines channel their efforts in a common direction. The Guest Editor of this Special Issue, William Edwards, is well known in the field of integrated circuits. His efforts in organizing, refereeing, and processing papers in this high quality issue are weil appreciated.