Part I describes interoperability and the current status of interoperability capability among law enforcement and public safety agencies. The key challenges and critical elements involved in achieving interoperability are considered and recent findings are presented concerning why public agencies are having problems communicating with one another. Part II turns to an analysis of how interoperability is achieved, beginning with a discussion of how to build a cooperative interagency foundation and how to conduct a needs analysis of local interoperability challenges. Part II offers guidance on creating a project plan for interoperability and advice for acquiring system components. Steps for implementing the interoperability program are presented and examples are offered from the implementation of interoperability programs in three small cities in Delta River County. This section of the guide also considers how to transition an interoperable system to long-term governance following successful implementation and offers a framework for the development of policies and procedures related to the communication system. Maintaining the technology and measuring interoperability are reviewed before the guide turns to an analysis of various communications technologies in Part III. Different technological approaches to interoperability are reviewed along with the specific types of communications equipment used for each approach. Both voice and data communications systems are considered in Part III, including radio technologies, wired data networks, and wireless data networks. Emerging and planned technologies are also reviewed, such as broadband wireless access for public safety and wideband wireless standards for public safety. This guide is intended as a companion to the “Law Enforcement Tech Guide: How to Plan, Purchase, and Manage Technology (Successfully!), A Guide for Executives, Managers, and Technologists.” Figures, appendixes, bibliography