This monograph presents physical and technical fundamentals of most ultrasonic processes used in industry such as US processing of thermoplastics (welding, riveting, flanging, embedding, cutting, etc.) and of metals and metal alloys (joining, plastification, stress relieving, measurements of elasticity moduls , reception of acoustic emission, etc.) with application examples and practical instructions as well as with qualitative theoretical calculations of the dissipated US vibration energy and heat production including all US basic parameters (generator power, vibration amplitude and resonance frequency, exposure time) and all material parameters (storage and loss elasticity moduls, density, heat capacity), which allows the process parameters to determin and to set in advance.The monograph is recommended for students, engineers and scientists in this field.