The IAEA Nuclear Security Series provides guidance for States to assist them in implementing a national nuclear security regime and in reviewing, and when necessary strengthening, this regime. The series also provides guidance for States to fulfil their obligations and commitments with respect to binding and non‑binding international instruments. The Nuclear Security Fundamentals set out the objective of a nuclear security regime and its essential elements in IAEA Nuclear Security Series No. 20, Objective and Essential Elements of a State’s Nuclear Security Regime . The IAEA Nuclear Security Recommendations indicate what a nuclear security regime should address in IAEA Nuclear Security Series Nos 13, Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/Revision 5); 14, Nuclear Security Recommendations on Radioactive Material and Associated Facilities; and 15, Nuclear Security Recommendations on Nuclear and Other Radioactive Material out of Regulatory Control