In this book, we present both the theoretical part and a number of applications that allow the use of wavelets in solving problems encountered in engineering. In the early part, we present a methodology that involves the moment method using as expansion function and Haar wavelets as pulse function weighting in determining the surface charge density in both dimensional and two-dimensional case. Posteriorly we present a series of applications that use various types of wavelets in solving problems involving electromagnetism, electrostatics, healthcare, and financial markets. This book presents a brief history, showing the development of the method of moments, some types of wavelets, such as Haar, Shannon and Mexican Hat and later the full application on electromagnetism by applying the Haar wavelet. This methodology equated the problems and applied to a finite straight wire and flat plates with negligible thickness, both subjected to a constant potential. As the matrix of the transformed Haar wavelets are scattered through a mathematical device can select a threshold, percentage that will drop values close to zero, with no major changes in the finish result, considerably reducing the execution time of programs.