"Design Data for Reinforced Plastics" assists the designer and user of reinforced plastics or composites to select the best combination of fibre and matrix for a specific application. Composites are versatile materials with unique properties. However, they differ from conventional materials and design data are less plentiful and more widely dispersed. The authors have assembled a systematic set of design parameters describing short and long term mechanical, thermal, electrical, fire and environmental performance, for composites based primarily on continuous glass, aramid and carbon fibres in thermosetting and thermoplastic matrices. Because proper fabrication is essential for a successful reinforced plastic component, this, and the associated topic of quality assurance, are considered in depth. Data have been collected and evaluated on a world-wide basis from published and unpublished sources, including raw materials suppliers. This process has been greatly assisted by access to the RAPRA composites database and that of PERA International on impact properties. The raw materials used in composites and fabrication methods have developed very rapidly in the last two decades and data has been assessed for reliability and relevance to current systems.