Since the beginning of the rubber and plastics industries, an essential requirement has been that the materials and the products are tested for quality control, to establish their fitness for purpose and to provide design data. This book gives a unique personal account of the developments in the technology of physical testing of polymers and of the changes in the working environment in which testing was conducted over the last fifty years. The authoritative account reflects the author"s position heading the testing laboratories at RAPRA and his involvement in international standardisation for many years. Much of the structure of the book is based on the editorials that have appeared over the thirty years that the author has been the editor of Polymer Testing Journal. They cover observations on the evolving changes in the conditions and attitudes in laboratories, the interaction of commercial and social pressures and the revolutions in instrument and information technology that have impacted on testing. In providing an appreciation of the past history of testing, it is intended that this volume will contribute to the further development of testing rubbers and plastics in the future.