Composite materials are increasingly finding use in diverse applications requiring a wide range of property and performance requirements. Low density, high specific strength and stiffness are the main features that make composite materials most suitable for structural applications. The field covers the concurrent manipulation of the material's composition and of the internal architecture of the composite in order to obtain the desired properties. The ability to tailor composite materials precisely is of great importance in structural applications. A systematic approach to the optimum tailoring of composite materials is a challenging design problem. The focus should be on the practical design aspects, and that is what is addressed in this special-topic volume.The design of structural composites requires that a balance be struck between processing technology, mechanical testing and numerical simulation, in order to obtain the optimum weight-strength-stiffness combination for a given application and industrial requirement. A variety of manufacturing processes and tests exist by which to characterize the mechanical properties of assorted models. Despite the complexity of composite structures and the diverse possibilities offered by the materials, this special-topic volume shows that certain techniques and rules can always be used to evaluate their behaviour and choose their structure.Included in this volume are nine articles on polymer-matrix composites, three articles on metal-matrix composites and one article on polymer composite-grid-reinforced concrete. These articles cover all of the aspects described above.   The knowledge gained by the attentive reader can be used to design better composites having improved mechanical properties.