Three decades ago, many diagnosis knowledge-based systems have been developed in different diagnostic domains. The diagnosis systems may provide different solutions for the same problem. These solutions mirror different viewpoints for different experts. This book presents a framework for multi-agent diagnosis system as an effective solution for the problem of acquiring different diagnostic results when consulting different diagnostic systems. The framework defines how the agents can negotiate, and cooperate together to resolve the belief conflict that may arise among them. The framework can be applied in any diagnostic domain. Also, the book presents a system prototype in the plant disorders domain. The prototype has been developed on the basis of this framework as a real case study. This book is very interesting for post-graduate students and researchers who have interested in the research areas of multi-agent systems, conflict resolution, diagnosis systems, and agent interaction protocols. The book is also important for practitioners who are developing standalone knowledge-based systems and want to take step forward to developing multi-agent systems.