This book constitutes the refereed proceedings of the First European Conference on Intelligence and Security Informatics, Euro ISI 2008, held in Esbjerg, Denmark, in December 2008. The 23 revised full papers and 2 revised poster papers presented were carefully reviewed and selected from 48 submissions. The papers are organized in topical sections on criminal and social network analysis, intelligence analysis and knowledge discovery, Web-based intelligence monitoring and analysis, privacy protection, access control, and digital rights management, malware and intrusion detection, as well as surveillance and crisis management.