Almost half a century has passed since the first practical use of microwaves in 1940's. During this period, extensive research and development have lead us to steady progress in terms of usable frequencies, fabrication capability of active and passive devices, transmission lines, and device integration density. An overview of this half-century progress in microwaves is presented, and topics of common interest are discussed from the following points of view: (1) Exploiting frontier frequencies from VHF to millimeter-wave and optical frequencies, (2) Transition from vacuum tubes era to solid-state devices era, (3) Transition from waveguides and discrete circuits era to planar integrated circuits era, (4) Wide-ranging applications of microwaves.