The report explores how Sweden during the last 40 years, at a national level, has handled vulnerability issues concerning infrastructures for electric power supply, telecommunication and information technology. For each infrastructure there is an historic overview of the development of the systems and their vulnerabilities. Measures taken at a national level for each of the infrastructures is then presented. Finally the report identifies important factors that has influenced the choice of measures. Examples are: - the development of electronics and computers - threat of electronic attacks - threat from military sabotage units - threat of precision bombing - the end of the Cold War - market reforms