Radioactive waste repositories are designed to isolate waste from the living environment without human intervention over extended periods of time. Nevertheless, the intention is not to abandon the repositories, but to provide the oversight that is necessary to ensure that they are not forgotten by society. In response to this challenge, the NEA launched the international initiative "Preservation of Records, Knowledge and Memory (RK&M) Across Generations" in 2011. As a result, an in‑depth understanding of this issue was developed, as well as a specific methodology to address it. This report serves as a general guide to the RK&M preservation topic. It presents a historical review, addresses ethical considerations, analyses the fundamentals of RK&M preservation, outlines various mechanisms and indicates how to develop these mechanisms into a systemic RK&M preservation strategy. It also aims to inspire and assist a variety of actors so that they can discuss and develop national and repository‑specific RK&M preservation strategies.