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.