This book constitutes the thoroughly refereed post-proceedings of the Second International Service Availability Symposium, ISAS 2005, held in Berlin, Germany in April 2005.

The 15 revised full papers presented together with a keynote talk were carefully selected for inclusion in the book. The papers are organized in topical sections on data and computation availability, specifying, modeling and verifying service availability, high-availability by service-oriented architectures, modeling and composition, and verification and availability assessment.