Materials science and engineering course has come into its own as a field of endeavour during the past 25 years. The central theme in this development is the concept that the properties and behaviour of a material are closely related to the internal structure of that material. The properties (which may be regarded as the responses of the material to its immediate environment) are functions of: (i) the kinds of atoms present and the type of bonding among them, and (ii) the geometrical arrangement of large numbers of atoms, microstructure and macrostructure. As a result, in order to modify properties, appropriate changes must be made in the internal structure. Also, if processing or service conditions alter the structure, the characteristics of the material are altered. Over the same period, noticeable changes have taken place in the teaching of engineering materials to the engineering students. Previously, elementary courses emphasised on the mechanical properties of materials with long dull lists of chemical specifications and descriptions of processing. More recently, elementary courses seek to provide a thorough grasp of the structures encountered in the principal families of materials - metals, ceramics and polymers - and then to show how the properties of important engineering materials depend on these structures. This course seeks to provide a background knowledge of the more commonly used engineering materials. This will be achieved by promoting an understanding of the interrelation of structure and properties in the principal families of materials and the mechanisms by which the structural changes may be accomplished.