The fundamental principles, physical models, and design fundamentals of three-dimensional microwave integrated circuits are presented. The principles of mathematical modeling of transmission lines and basic elements are discussed. The topological approach to the description of the electromagnetic field in the elements of three-dimensional microwave integrated circuits is examined at the electrodynamic level. The structures of the base elements, functional units, and devices for processing signals from pickups as well as the physical and technological aspects of their fabrication based on three-dimensional microwave integrated circuits are examined.