ICRP Publication 81 deals with the radiological protection of members of the public following the disposal of long-lived solid radioactive waste using the ‘concentrate and retain’ strategy. It covers options including shallow land burial and deep geological disposal. Its recommendations apply to new disposal facilities. The report supplements, updates, and clarifies the material in ICRP Publication 46 from 1986, taking into account the most recent general recommendations of ICRP in Publication 60 and the general ICRP policy for disposal of all types of radioactive waste as described in Publication 77. It addresses the main protection issue: exposure that may or may not occur in the far future, and regards constrained optimisation as the central approach to evaluating radiological acceptability of a waste disposal system. In this context, optimisation is a judgmental, essentially qualitative process. Two categories of exposure situation are considered: natural processes and human intrusion.