During the period May 2000 until December 2003 the Swedish Defence Research Agency, FOI have been conducting research and other knowledge production within the research program SAVI (assurance of critical infrastructure). The program was commissioned by the Swedish Emergency Management Agency, SEMA. The objective of the research program has been to establish a capability for strategic knowledge production and within Sweden secure a high level of competence regarding assurance of critical infrastructure. The program has been focused on creating fundamental knowledge on infrastructure systems, the internal and external interdependencies of infrastructures, the threats against critical infrastructures, infrastructure vulnerabilities, the consequences of infrastructure failures and possible measures to assure critical infrastructure. The goal has been to provide coherent and systematic knowledge production that can contribute to the reduction vulnerabilities in critical infrastructure. The purpose of the report is to give an overview of the work and activities within SAVI. This synthesis report has the format of an anthology,where the textshave been selected from different studies and reports within the research program.