The efficiency of Ultrasonic Machining (USM) varies with the displacement amplitude of working face of the tool. The amplitude of vibration is increased by means of focusing element is called "concentrator" or "Acoustic Horn" or "Velocity Transformer". One end of the horn is fixed to vibration generator i.e., transducer (usually the bigger end) and the tool is attached to the smaller end. In industry, the shape and the length of a horn are obtained by experiments or rules of thumb; hence they consume much more materials and time. Moreover, the performance does not reach the maximum due to a poor design. Much of the research has been done for horns of regular profiles i.e., stepped, conical and exponential. The purpose of the book is to design efficient concentrators of different other profiles i.e., Catenoidal and Bezier profiles with the aid of Finite Element Analysis Techniques and assessing the performance of the horn by a comparative study against stepped and conical horns.