DR. GEOFFREY GEE, who has recently been appointed director of the British Rubber Producers' Research Association's extensive laboratories at Welwyn, has made important contributions to our knowledge and understanding of the properties of long-chain polymers, especially rubber. His early work at Cambridge dealt with the kinetics of polymerization reactions both in bulk and at interfaces. More recently, he has undertaken a critical examination of the thermodynamics and statistical mechanics of systems involving rubber and related polymers. The last decade has witnessed striking advances in the mathematical treatment of the behaviour of long-chain molecules, but there has been a dearth of exact experimental data, thus precluding any development of the statistical mechanical treatment. Dr. Gee with his collaborators has been able to provide reliable and extensive experimental data which have permitted them in turn to make advances in the theoretical treatment. The determination of the molecular weights of rubbers and the inter-relationship of the different methods ; the connexion between the heats of mixing of rubber and liquids and their cohesive energy densities constitute two of the more important sections of his work.