Book excerpt: PURPOSE Since the publication of the previous, Fifth Edition of this volume in 1991, the 'advanced' sector of the world-wide composites industry in particular, has seen many company changes in reorganisation, realignment and ownership. These changes have affected the raw material suppliers as well as those moulding the finished product. Changes in the demands of the aerospace, defence and allied industries have largely been the cause. That situation has been particularly true for those manufacturing and distributing reinforcement fibres and fabrics, necessitating this comprehensive Sixth Edition revision. However publication is also timely, because a major and important consequence is the better consideration now being given by the 'commercial' market sector, to the use - and advantages - of some of the carbon, aramid and other high-performance reinforcements, described within these pages. Although supplying at a much lower finished component cost than applies for the aerospace and defence markets, the total tonnage output answering the typically lower-performance requirements of the 'commercial' sector, is higher by many factors. Overall therefore, the summation of output tonnage and price, will continue to favour the latter. Nevertheless this 'commercial' market sector must, albeit slowly, ultimately benefit to a marked degree from an increasing technology spin-off, promoted to an extent somewhat earlier than might otherwise have been expected, by the noted changes in market place demand.