This book constitutes the refereed proceedings of the three international workshops PAISI 2008, PACCF 2008, and SOCO 2008, held as satellite events of the IEEE International Conference on Intelligence and Security Informatics, ISI 2008, in Taipei, Taiwan, in June 2008.The 55 revised full papers presented were carefully reviewed and selected from the presentations at the workshops. The 21 papers of the Pacific Asia Workshop on Intelligence and Security Informatics (PAISI 2008) cover topics such as information retrieval and event detection, internet security and cybercrime, currency and data protection, cryptography, image and video analysis, privacy issues, social networks, modeling and visualization, and network intrusion detection. The Pacific Asia Workshop on Cybercrime and Computer Forensics (PACCF 2008) furnishes 10 papers about forensic information management, forensic technologies, and forensic principles and tools. The 24 papers of the Workshop on Social Computing (SOCO 2008) are organized in topical sections on social web and social information management, social networks and agent-based modeling, as well as social opinions, e-commerce, security and privacy considerations.