Over the last five years an enormous number of wind turbines have been installed in Europe, bringing wind energy into public awareness. However, its further development is restricted mainly by public complaints caused by visual impact and noise.The European Commission has therefore funded a number of research projects in the field of wind turbine noise within the JOULE program. This book presents the most relevant results of these projects.The book addresses all relevant aspects of wind turbine noise, namely: noise reduction, noise propagation, noise measurement, and an introduction to aeroacoustics. It may serve as a first reference in the field of wind turbine noise for researchers, planners, and manufacturers.