This volume is the eighth in the Intelligent Agents series associated with the ATAL workshops. These workshops on “Agent Theories, Architectures, and Languages” have established themselves as a tradition, and play the role of small but internationally well-known conferences on the subject, where besides theory per se also integration of theory and practice is in focus. Specifically, ATAL addresses issues of theories of agency, software architectures for intelligent agents, methodologies and programming languages for realizing agents, and software tools for applying and evaluating agent-based systems.