This presentation has been revised and updated to newly published editions of NFPA 921, Guide for Fire and Explosion Investigations—2021, and NFPA 1033, Standard for Professional Qualifications for Fire Investigator--2022, in addition to changes to the original NFPA 1037, Standard for Professional Qualification for Fire Marshal, which is now included in the new consolidated NFPA 1030 (2024) document. Of significant interest to all fire investigators is the soon-to-be-released NFPA 1321, Standard for Fire Investigation Units, slated for 2024, which will significantly impact all fire investigators and all fire investigation units. This program is designed to demonstrate that a comprehensive, thorough, and systematic examination of every fire scene in accordance with NFPA 921 is of paramount importance and that the "investigator" conducting that fire scene exam needs to adhere to and be "qualified" to conduct that investigation per NFPA 1033 and NFPA 1037, the accepted standards for a "Fire Investigator" and a "Fire Marshal." The "investigator" must have a process in hand that facilitates the investigation of the entire scene and that allows for the proper documentation of that scene, the correct elimination or attribution of the heat source responsible for the fire, and the accurate determination as to the area or point of the origin of the fire. The presentation will also discuss the preparation of a viable investigative report, which will memorialize an accurate record of the investigation for use later in either a departmental, civil, or criminal process or proceeding.