This book constitutes the refereed proceedings of the 5th International Conference, ICGS3, held in London, UK, in September 2009. The 28 revised full papers presented together with 3 keynote papers were carefully reviewed and selected from many submissions. The two days conference focused on the challenges of complexity, rapid pace of change and risk/opportunity issues associated with modern products, systems, special events and infrastructures. The importance of adopting systematic and systemic approaches to the assurance of these systems was emphasized within a special stream focused on strategic frameworks, architectures and human factors.