The development of microwave ferrite materials and devices over the last thirty years is traced. The status of materials, devices, and theoretical understanding prevalent in the mid-1950s is first reviewed. Developments in materials engineering of garnets and lithium ferrites in the 1960s and 1970s are described, along with the evolution of circulators and phase shifters. Current levels of performance achievable in circulators and phase shifters are described, and future challenges and opportunities are discussed. >