This is a comprehensive work concerning the basic principles of plate theory and its methodology, in which the author includes both plastic and elastic responses in his discussion. The reader is taken from relatively elementary aspects of the topic right through to the most recent research findings. The less experienced reader should benefit from the revision of basic mathematics in the preliminary chapter, and from the worked examples and exercises throughout the book. For the reader with some previous knowledge of plate theory, there is a stimulating discussion of the geometry of surfaces, reference to the most modern applications of plate theory, and an annotated bibliography. The features new to this edition include a treatment of the lower bound methods for plate collapse load studies, and the introduction of a new chapter on the new technology - externally reinforced concrete.