A number of imaginative approaches to improve earthquake response performance have been developed and others are forthcoming. The effects of adding supplemental damping devices to building structural systems in terms of its seismic response, the characterization of equivalent viscous damping for hysteretic damping devices, and a description of several supplemental damping devices are presented. It is concluded that supplemental damping devices can provide dependable energy dissipation during earthquakes thereby resulting in improved performance of structures.