The document "ATP 2-01.3 Intelligence Preparation of the Operational Environment" from March 2019, approved for public release with unlimited distribution, updates and supersedes previous publications on the topic. It introduces changes to align with the updates in FM 2-0, Intelligence (dated October 2023), and JP 2-0, Joint Intelligence (dated May 2022). The changes include the modification of terms from "intelligence preparation of the battlefield" to "intelligence preparation of the operational environment" (IPOE), updating acronyms, terms, tables, and figures to reflect current doctrine and eliminating obsolete information. This publication is accessible through the Army Publishing Directorate and Central Army Registry websites. The document, under the authority of the Department of the Army, outlines the systematic process of analyzing mission variables (enemy, terrain, weather, and civil considerations) in an area of interest to determine their effect on operations. It emphasizes the importance of IPOE in the military decision-making process, supporting planning, decision-making, and the development of intelligence products critical for operational success. The initial chapters cover fundamental principles, process activities, relationships, and the IPOE's four-step process: defining the operational environment, describing environmental effects on operations, evaluating the threat, and determining threat courses of action. It discusses staff collaboration and the integration of intelligence in operational planning to enhance situational understanding and decision-making. This summary covers the first 24 pages out of 233, focusing on the publication's introduction, updates, and foundational concepts of IPOE. For a complete understanding of the document and its applications in operational planning and intelligence analysis, a thorough review of the entire publication is recommended.