This book is intended as a textbook for the course of ''Theory of Elasticity'' offered in universities and colleges of engineering. It can also be used as a reference book for engineers. In this book plane problems are discussed first. After the reader has obtained a preliminary knowledge of the basic theories and problem-solving methods of the course, spatial problems are dealt with, followed by discussions on problems in plates and shells. On the whole, this arrangement meets the principle of proceeding gradually from the basic and the easy, to the complex and difficult materials and is helpful for teaching and learning. In elucidating fundamental principles and deducing basic equations, the author has endeavoured to render mathematical derivation explicit and concise and to avoid using abstruse and overelaborate mathematical reasoning which is likely to over shadow physical concepts. In expounding problem-solving approaches, the author not only dwells on the nature of the approaches and their applications in engineering problems, but also emphatically points out the mode of thinking in analysing problems and the proper way of solving problems.