The primary purpose of this book is to present methods for analyzing the stresses and deflections developed in any given type of structure when it is subjected to an arbitrary dynamic loading. In one sense, this objective may be considered to be an extension of standard methods of structural analysis, which generally are concerned with static loading only, to permit consideration of dynamic loading as well. In this context, the static-loading condition may be looked upon merely as a special form of dynamic loading. However, in the analysis of a linear structure it is convenient to distinguish between the static and the dynamic components of the applied loading, to evaluate the response to each type of loading separately,and then to superpose the two response components to obtain their total effect. When treated thusly, the static and dynamic methods of analysis are fundamentally different in character.