This supplement is an update of Technical Report Series No. 318, Compendium of Neutron Spectra and Detector Responses for Radiation Protection Purposes (1990), that takes into account the major changes in the recommended energy dependence of risk related quantities, the increased importance of high neutron energies, the increased use of boron neutron capture therapy, promising new developments in detector design, new measured workplace spectra and improved calibration facilities. It includes the fluence to dose equivalent conversion coefficients for the recently recommended radiation protection quantities and a large number of fluence response functions for recently developed or improved detectors, as well as over 200 new spectra. Contents: Chapter 1. Introduction; Chapter 2. Dosimetric quantities; Chapter 3. Multisphere, survey instrument and dosimeter responses; Chapter 4. Calibration and reference spectra; Chapter 5. Operational spectra; Chapter 6. Use of data from the previous compendium; Appendix: Examples of compendium allocations; References.