This book Computer Modelling of Seas and Coastal Regions is the first volume of the two volume proceedings of the International Conference on Computer Modelling of Seas and Coastal Regions and Boundary Elements and Fluid Dynamics, held in Southampton, U.K., in April 1992. The importance of accurate modelling of seas and coastal regions is empha sized by the need for predicting their behaviour under extreme conditions. Problems, such as pollution of these areas, have become a major interna tional concern and the related environmental problems need further study using techniques which can be used to determine the ways in which the water systems respond to different effects and try to minimize the damage. They can also lead to the development of early warning systems in combina tion with remote sensing equipment and experimental sampling techniques. Furthermore, once a disaster occurs, the model can be used to optimize the use of the available resources. The conference addresses coastal region modelling both under normal and extreme conditions, with special reference to practical problems, currently being experienced around the world. Many of the delegates are actively involved in the modelling of seas and coastal regions. This volume includes sections on waves, tides, shallow water circulation and channel flow, siltation and sedimentation, pollution problems, and computu tational techniques. The organizer would like to thank the International Scientific Advisory Committee, the conference delegates and all those who have actively sup ported the meeting.