<DIV>Light water reactors are the predominant class of nuclear power reactors in operation today. However, aging and degradation can influence both the performance and lifetime of components. Knowledge of these factors is therefore critical to the provision of safe, continuous operation in either the short or long term. Routes to measure and mitigate these aging and degradation problems, and to assess residual lifetime, are critical to the materials management, maintenance and safety planning for the plant.<BR><BR>The editor and contributors provide a comprehensive and systematic review of materials aging and degradation mechanisms prevalent in light water reactor environments, the specific effects on the main reactor components, and the applicable mitigation routes and materials management approaches used to handle these effects. Part one introduces fundamental aging issues and degradation mechanisms and discusses corrosion in pressurized water reactors and creep deformation of materials in light water reactors. Subsequent sections consider materials aging and degradation in specific light water reactor components alongside the aging of electric cables and focus on materials management strategies for light water reactors, pressurized water reactors and VVER reactors. The conclusion explores materials-related problems faced by light water reactor operators and corresponding research needs.</div>