Areader who achieves a substantial command of the material con tained in this book should be able to read with understanding most of the literature in the field. Possible exceptions may be certain special aspects of the subject such as the aeroelasticity of plates and sheIls or the use of electronic feedback control to modify aeroelastic behavior. The first author has considered the former topic in aseparate volume. The latter topic is also deserving of aseparate volume. In the first portion of the book the basic physical phenomena of divergence, control surface eflectiveness, flutter and gust response of aeronautical vehicles are treated. As an indication of the expanding scope of the field, representative examples are also drawn from the non aeronautical literature. To aid the student who is encountering these phenomena for the first time, each is introduced in the context of a simple physical model and then reconsidered systematicaIly in more compli cated models using more sophisticated mathematics.