Nuclear forensics supports national nuclear security measures and criminal investigations by providing information on the identity, origin and history of nuclear or other radioactive material found out of regulatory control. This publication provides information for States on the use of nuclear forensics in response to criminal or other unauthorized acts involving nuclear or other radioactive material, based on the guidance provided in IAEA Nuclear Security Series No. 2-G (Rev. 1), Nuclear Forensics in Support of Investigations. It is intended for technical and non-technical personnel responsible for developing nuclear forensic analytical capabilities within the context of a broader national nuclear forensic programme stemming from national legislation. It provides technical information that describes the application of specific methods, analytical techniques and technical expertise used for nuclear forensic analysis in support of investigations of criminal or other unauthorized acts involving nuclear or other radioactive material.