This book addresses the general problem of the derivation of the shadowing function from randomly rough surfaces. This topic is important for many applications like the wave scattering from rough surfaces both in optics and radar domains and also in the computer graphics for the calculation of the bidirectional reflectance distribution function. This book presents an overview and recent advances of this topic by detailing this progress. First, the simpler problem is investigated, that is, monostatic case - one-dimensional (1D, or 2D problem) surface - one reflection, ending by the more complicated problem, that is bistatic case - 2D surface (or 3D problem) - multiple reflections. In addition, the authors will focus on the introduction of the simplifying assumptions to derive closed-from expressions of the shadowing function and will quantify their impact on the accuracy of the resulting models. In addition, applications of the shadowing function in problems encountered in physics will be addressed. The problem of the derivation of the shadowing function from a rough surface is at the boundary between several scientific communities, each with its terminology. This book will make the link between these different communities and will help the reader to understand the theoretical aspects of this problem while giving practical applications.