These new systems call for a coherent framework that guides their actions as chatbots and conversational agents. Human–Robot/Agent assessment mechanisms naturally lend themselves to this task. As these systems increasingly assist humans in a multitude of tasks, the ethics of their existence, their design and their interaction with users are becoming crucial issues. This book discusses the essential players and features involved, such as chat-based agents, multi-domain dialog systems, human–robot interaction, social dialog policy, and advanced dialog system architectures.