Due to the recent earthquakes in the U.S. and Japan, many modern buildings ceased functioning and required costly structural and nonstructural repairs, although they successfully protected the lives of the occupants. Because of these, most major buildings constructed after the earthquakes utilize either passive-control scheme or base-isolation scheme in order to better protect the building and its contents. This paper addresses current status of passive control technology being implemented in Japan. Four major groups of dampers and their basic mechanisms are discussed. Three groups of frames are explained, referring to different connection schemes and deformation lags between the frame and damper. A unified approach to assess effectiveness of various dampers and frames will be presented.