Piezoelectric elements have been widely used in recent past to detect cracks and damages of plates in aerospace applications. This book investigates the characteristics of the piezoelectric elements, and their usability to monitor the wear characteristics of cutting tools. The experimental procedures adopted to evaluate the utility performance of piezoelectric actuators are elaborately discussed in the book. Frequency response/non linear characteristics of piezoelectric elements are revealed, and the methodology used to obtain optimum electrical response received from the actuators is explicated. The book also describes how piezoelectric actuators are used as sensors, and receiving resonators, to monitor wear levels of an End mill. Further, it describes how Surface Elastic Waves and Frequency Response to Excitation techniques are compatible for wear monitoring, with piezoelectric elements as sensors. Data acquisition and signal processing techniques followed in this study are intricately demonstrated to effectively classify the levels of Mill wear during its operation.