Dr. Werner discusses the vast range of new synthetic materials available with the aim of enabling the conservator to choose the correct material for the job. He mentions briefly the general structure of the synthetic resins from the chemical point of view including the use of plasticizers. Many of these resins are used as adhesives and consolidants and he sets out an appropriate method of classification founded on the nature of the reaction whereby the material sets from the liquid to the solid state. Dr. Werner then goes on to discuss the amount of shrinkage on setting and describes tests carried out in the British Museum Research Laboratory. He then discusses in some detail the properties of certain individual synthetic resins and their use in the development of new and improved methods of conservation. Epoxy resin, polyester resins, soluble nylon, synthetic waxes and polyvinyl acetate and polyacrylates are dealt with, in each case related to some particular problem of conservation. Manufacturers' names are also given. Finally he stresses the fact that indiscriminate use of synthetic materials without a proper knowledge of their essential properties can prove disastrous.