Mechanics of materials is an important introductory course that aims to provide fundamental theories for the design of engineering structures. As a prerequisite to further studies on in mechanics, this course has received significant attention to become nowadays essential and compulsory for undergraduate students majoring in engineering. The Department of Engineering Mechanics of Dalian University of Technology is a leading institute in the field of computational mechanics and engineering science in China, and has grained substantial experience in the teaching of Mechanics of materials. Authors of this book presents their core teaching materials which have distinctive features in the combination of computer science and engineering, and of theory and practice.