This book provides principles and guidelines to help engineers design supplemental damping devices to reduce earthquake-induced structural vibrations-especially when the level of damping is high or when nonlinearities are important design issues. It tackles limitations of conventional design practice and explores how to improve them to handle enhanced damping. The book reviews structural dynamics theory, introduces design principles for commonly used dampers, and explores more detailed procedures based on the classification of specific damping devices according to their linearity. It helps engineers select the most effective type of damper and determine the amount and configuration of damping under given working conditions.