In this chapter, we discuss the numerical analysis of light propagation in homogenous media. It is assumed that the reader is familiar with wave optics, electromagnetic optics, and Fourier optics (see [1,2]). In particular, we discuss the application of the Fourier method. In the first section, we discuss the application of the Fourier method to study optical beam propagation in homogenous media. In the second section, we extend the Fourier method and study optical beam reflection and refraction. In the third section, we discuss the application of paraxial and wide angle approximations. Finally, in the last section, we discuss the modelling of optical systems that include thin bulk optical elements. In this chapter, we also introduce several basic concepts that are further explored in the remaining chapters of this book. A description of the application of ray optics methods can be found in Poon and Kim .