Since the third edition of this book was published in 1988 there have been no startling changes in the materials used for the construction of swimming pools. A similar comment can be made about the design of reinforced concrete swimming pool shells. The number of swimming pools has continued to increase both in the public and private sectors. This is particularly so with private club leisure centres which offer a wide range of activities. There has been significant developments in the field of National Specifications and Code of Practice relating to construction due to the intensive work on the preparation of Euro Standards and Codes and the issue of Directives from the EEC. The latter set out minimum quality standards for a wide range of constructional materials, and establish the responsibility of suppliers and designers.