This book contains 38 papers presented at the seventh Working Conference on 'Reliability and Optimization of Structural Systems' held at Boulder, Colorado, USA, on April 2-4, 1996. The Working Conference was organized by the IFIP (International Federation for Information Processing) Working Group 7.5 of Technical Committee 7 and was the seventh in a series of similar conferences. The objectives of the Working Group and hence this publication are: - to promote modern structural systems optimization and reliability theory, - to advance international co-operation in the field of structural system optimization and reliability theory, - to stimulate research, development and application of structural system optimization and reliability theory, - to further dissemination and exchange of information on reliability and optimization of structural systems, and - to encourage education in structural system organization and reliability theory.