This text is an introduction to the analysis of the mechanical behaviour of polymer/fibre composites for technologists and engineers. It is primarily designed as a teaching text with a substantial range of examples and solved problems included, which bring out the practical implications of the basic principles. The reader is encouraged to develop understanding of the basic principles at the level of physical intuition as well as by the use of detailed analysis. There are references to source books for more detailed discussions. The book states briefly the main themes of polymer/fibre composites to provide a context for the more detailed discussion of mechanical behaviour. Second, the philosophy and elementary concepts of solid body mechanics for a linear elastic isotropic material is addressed and this provided an introduction to the framework of our understanding assumed in the more advanced texts on composite mechanics. Third, the language of plate theory is introduced, and applied to a single ply of an isotropic material and them to a unidirectional ply. The vocabulary of laminates is presented, and a simple analysis is applied for laminates where constituent plies are isotropic or unidirectional. The strength of plies and laminates is discussed. Finally, the effect of change of temperature on mechanical performance of laminates is introduced, together with some comments about the stiffness of thin wall structures. This book should be of interest to undergraduate (middle and senior) and graduate students in materials, mechanical, production and chemical engineering departments. Also professional engineers in wide range of industries using composites (aerospace, automobile).