At intermediate energies, nuclear reactions have a crucial significance in nuclear physics and in science in general, which is reflected by the wide industrial scope of applications of these reactions. In this book, the fundamental theoretical ideas of the (Exciton Model), one of the most promising statistical models used to interpret such reactions, are listed, and some convenient calculations are made. Practical focus is given to the important quantity needed in this model, the (Level Density, LD). Taking the basic definition as a start, the LD is then calculated for a wide range of corrections, including Pauli principle, bound-state and finite well depth, pairing with suggested postulations, shell structure, active-passive holes, charge factors, and spin. LD is calculated in each case using a library of Matlab codes, listed in this book's material as their calling programs. The results of each count are briefly explained. This book is made of eight chapters, the first two give a general review, and the rest are combined with numerical calculations. The aim of this book is to present handy practices for researchers, specially nuclear physicists, interested in the exciton model.