9/11, Hurricane Katrina, and other calamitous events continue to challenge Federal, State, Tribal, Territorial, and local Search and Rescue (SAR) responders in the planning and execution of large-scale SAR operations. NSARC realizes the Federal government's response to large-scale Catastrophic Incident SAR (CISAR; pronounced "See-Eye-SAR") must continue to improve. As a result of feedback and lessons learned from previous CISAR operations, NSARC has revised and added several new Sections to the original Catastrophic Incident Search and Rescue (CISAR) Addendum to the National Search and Rescue Supplement (NSS.) In 2010, NSARC will focus its effort on updating the NSS. Meanwhile, it plans to update this CISAR manual as necessary at the conclusion of the 2010 hurricane season. There are many different Federal, State, Tribal, Territorial, and local SAR response cultures. Each possesses unique capabilities, language, and responsibilities. During a Catastrophic Incident, NSARC member Departments and Agencies are required to conduct multi-agency SAR operations within a unified command. This CISAR Addendum (Version 2.0) has been written to: (1) provide a concise description of the Federal Government's civil SAR response to catastrophic incidents; (2) guide Federal authorities involved in the response; and (3) inform States, Tribes, and Territories on what to expect from Federal SAR responders. Response to several catastrophic incidents has demonstrated that a unified command is crucial to an effective CISAR response. CISAR Addendum (Version 2.0) sets baseline guidance and principles that can improve the effectiveness of the unified command in the conduct of the CISAR, and provide important guidance for the CISAR.