**This document is the FBI's Domestic Investigations and Operations Guide (DIOG), outlining policies and procedures for domestic operations.** It details the authorities, purpose, and policies governing FBI employees involved in investigative and intelligence activities. **The guide addresses a wide range of topics, including investigative methods, surveillance techniques, the handling of sensitive information, and compliance with privacy laws and civil liberties.** It provides definitions for various roles, such as Task Force Officers, and outlines responsibilities for supervisors. **Furthermore, it covers specific scenarios, such as civil disorder investigations, extraterritorial provisions, and interactions with other law enforcement agencies.** The DIOG also emphasizes adherence to constitutional rights, particularly First Amendment protections, and provides guidance on intelligence gathering and analysis, as well as rules of information sharing within the government. **Overall, the DIOG serves as a comprehensive reference for FBI personnel to ensure lawful and effective domestic operations while safeguarding civil liberties.**