This volume in the Hydraulic Machinery Series is concerned with vibration-free and quiet operation of hydraulic machines. It deals with the problems caused by mechanical and hydraulic excitations in the hydraulic machinery (not with transients which are treated in a separate volume). The scope covers the fundamentals for analyses of the fluid structure systems, structural vibration, shaft rotordynamics and system instability. Noise and diagnosis are introduced with examples from practical problems. The invited authors from five continents are internationally recognized experts in their fields.