This book contains the proceedings of the 25th symposium of the International Committee on Aeronautical Fatigue that was held from 27-29 May 2009 in Rotterdam, the Netherlands. It contains 77 selected papers on a broad range of structural fatigue related topics. They all reflect in some way or another the ICAF 2009 symposium's theme "Bridging the gap between theory and operational practice", with particular emphasis on: Airworthiness considerations Advanced materials and innovative structural concepts Full-scale fatigue testing of aircraft and aircraft structural components Life extension and management of ageing fleets Structural health and structural loads monitoring NDI, inspections and maintenance Fatigue crack growth and life prediction methods Fatigue life enhancement methods and repair solutions Environmental effects Probabilistic modelling and risk analysis The book is an excellent read for anyone with an interest in aeronautical fatigue and aircraft structural integrity, from both a scientific and a practical point of view.