At the FIP Symposiu m on Concrete Sea Structures, which was held on 28-29 September 1 972 in Tbilisi, Georgia, the participants unanimously agreed that c oncrete was bound to play a major if not the leading part in the rapidly developing field of offshore construction. It was also agreed that the discovery of oil and gas in the North Sea had produced an immediate and exciting challenge in the demand for the construction of fixed structures in marine environments which, in terms of hostile natura! forces, would far exceed anything tackled by engineers to date. It was therefore decided to set up an FIP Commission on Concrete Sea Structures under the chairmanship of Mr Fr,óde Hansen which would report to the FIP Seventh Congress in New York in May 1974 . It seemed natura! to divide the tasks of the Commission into three working groups: Design, Materials, and Construction Methods. It soon became apparent that the demands for structures subjected to deep and hostile waters were so great and so pressing that it was decided to accelerate the work of the Design and Materials Working Groups, and to produce the first edition of these Recommendations before the New York Congres s . The Chairmen for the two Working Groups were Mr Kurt Eriksson and Dr Odd Gjprv respectively. The publication of these Recommendations has been made possible by the li vely interest of these two groups and by the valuable assistance of Mr D. Palmer and Mr B. Spratt of the C ement and Concrete Association and Mr M. D. Hazen of Sir Robert McAlpine & Sons Ltd. The Recommendations have been published with the approval of the FIP Administrati ve Council. The work of the Construction Methods Working Group has not been included in this edition since practical construction experience in this most challenging field is still quite limited. The successful completion of the Ekofisk Storage Tank has added tremendously to obtaining practical experience, and this, with the fact that two larger concrete offshore platforms will soon be under c onstruction, offers the promise that future editions will be augmented by some very valuable practical construction experience.