Designing a wind turbine is an interdisciplinary process that requires an understanding of challenges for all parties involved. The authors deliver an effective and economic way to organize such a design by respecting all the challenges involved. The book provides such insight by utilizing specific examples of existing modern designs. Detailed descriptions and explanations are given for those components of the wind turbine that are normally developed by the so-called original equipment manufacturers (OEM) of a particular type. The OEM needs to have full knowledge of the complete system that consists of all parts being rotor blades, nacelle, drive train, tower, and foundation including the dynamic properties and the response to the controller action. This full knowledge is called system competence. For a wind turbine the drive train is the most important system. It consists of many components like shafts, bearings, gearbox, and generator for a wind turbine with a gear box; in systems without a gearbox a large generator has to be integrated into the drive train.