This book will explore how the present, ad hoc U.S. federal, state, and local intelligence enterprise developed and its prospects for continued evolution. It will examine the types of threats that have warranted information sharing, the structures through which this information is shared, and areas where the current enterprise can be strengthened to make all levels of government more effective against threats to national security. This book will provide a baseline knowledge of how the federal, state, and local domestically-oriented intelligence enterprise has reached its current organization and provide a common point of reference for stakeholders and students (i.e. future stakeholders) to assess the enterprise's effectiveness and shortcomings. This book will be a valuable resource for both academic and practitioner audiences. Intelligence, criminal justice, and public policy programs at the undergraduate and graduate levels grapple with aspects of ensuring that the right information is shared and acted on in furtherance of national security. Additionally, practitioners - especially those responsible for developing the architecture for information sharing as well as those seeking a better understanding of the architecture they are using daily - will benefit from a resource that explains how and why the current system has developed and what course corrections are necessary to ensure that information can be exploited by federal, state, and local authorities to achieve a unified approach to national security.