Progress occurs when there is information sharing, communication among entities, interaction, and integration. Those interoperability needs exist in all types of organizations (e.g., public administration, non-profit and private). The increasing need for information exchange, the supply of online services to citizens, and the cost reduction of public operations demand that government organizations, and other public administration entities, be ready to provide an adequate interface to their stakeholders. Thus, an interoperability diagnosis provides an organization the opportunity to know its strengths and weaknesses and prioritize actions to improve its performance and capabilities. This book presents the Public Administration Interoperability Capability Model (PAICM) and the Public Administration Interoperability Diagnosis Method (PAIDM). A framework of how to extract performance measurement attributes and a real diagnosis case are also presented. The application of PAICM and PAIDM in public administration organizations shows results regarding their capability levels that can be used as inputs to interoperability processes improvements.