This Handbook for Military Participation in the Interagency Management System for Reconstruction and Stabilization is Book One in a set of five handbooks developed to assist the joint force commander design, plan, and execute a whole-of-government approach. Included with the series is an overview J7/J9 Pamphlet, Executive Summary of the Unified Action Handbook Series, that describes the handbooks, suggests how they should be used, and identifies the significant interrelationships among them. The handbook outlines joint force roles and responsibilities in the Interagency Management System (IMS) and existing interagency coordination authorities and mechanisms. It aligns with the USG Planning Framework for Reconstruction, Stabilization, and Conflict Transformation. It will also align with the IMS Guide under development at the Department of States' Office of the Coordinator for Reconstruction and Stabilization.