This book is primarily a textbook written for engineers, students and teachers, and for people working on fatigue problems of engineering structures and materials. The book can be used for graduate and undergraduate courses, workshops, and short courses for people working in the industry or research institutes. The book also offers useful comments for researchers in view of the practical relevance of investigations and to plan future research. An important theme of the book is the understanding of what happens in the material of an engineering structure subjected to a spectrum of cyclic loads in service. Knowledge of the fatigue mechanism in the material and how it can be affected by a large variety of practical conditions is essential for dealing with fatigue problems. The structure must be designed for durability, and thus against fatigue. This includes not only the overall concept of the structure and safety and economic aspects, but also questions on detail design, joints, production and material surface quality. The designer must predict the fatigue performance of the structure. Knowledge of the various influencing factors is essential. Similar considerations arise if fatigue problems occur after a period in service when decisions have to be made on remedial actions. A unique feature of the book is the integrated approach to fatigue of engineering structures as outlined in the picture on the front cover of the book.