The constant need for cost-effective structural forms has led to the increasing use of composite construction, and a substantial amount of research effort is currently being spent in developing techniques for combining concrete and steel effectively. Significant economies in this form of construction have been observed, especially in bridges and building floors. Codes of Practice on composite construction are being revised in the UK and in Europe, in the light of the substantial amount of knowledge that has been generated in recent years. An International Conference organised by the Department of Civil and Structural Engineering, University College, Cardiff, UK, with the specific objective of discussing all types of metal structures in an integrated way, provided a forum for the dissemination of new concepts and for reviewing developments; the expectations of the organisers have been amply justified and exceeded by the level of international response to the call for papers. This volume contains 17 papers on composite steel structures, presented at the Conference, many of which were by well-known experts in their respective fields.