[en] This handbook contains nuclear data needed by safeguards users for their work. It was initiated by an IAEA Working Group. The contents were defined by the replies to a questionnaire sent to safeguards specialists, and restricted by the availability of evaluated nuclear data. This revised edition was updated after review of the preliminary issue by safeguards and nuclear data experts and when updates of nuclear data libraries were released. The handbook contains the following basic nuclear data: Actinides; nuclear decay data; thermal neutron cross sections and resonance integrals; prompt neutron data; delayed neutron data. Fission products; nuclear data; thermal neutron capture cross sections and resonance integrals. Fission product yields. (author)