This book provides essential knowledge and techniques required to assess materials for extending the life of ageing offshore structures used for energy production. With over half of these structures currently in a life extension phase, the effects of ageing and degradation are at the forefront of the industry.The book presents the changes in industry practices and key technological advancements that have shaped the field since its inception. It reviews the original properties of the materials employed in offshore structures and provides a deep understanding of their behaviour as they age over time. The relevant degradation processes are investigated for offshore structural materials such as steel, welds, bolted joints, concrete, grout, reinforcement, pre-tensioning and non-metallic materials (including coatings and composites). Materials engineers will be equipped with the necessary tools in this book to evaluate materials in existing ageing structures.The book goes beyond theoretical knowledge, providing practical insights into assessing the performance of materials in ageing structures. With a focus on ensuring the efficient and safe continued use of existing infrastructure, engineers will find useful guidance to inform decision-making and facilitate the assessment process. The book brings together a wide range of research findings relevant to the topic and offers an updated summary of material assessment techniques that are largely difficult or even impossible to access publicly.This book is an invaluable resource for practising materials engineers, offshore engineering professionals, or materials engineering students.