This book presents classical asymptotic models used to describe the electromagnetic wave scattering from rough surfaces. It focuses on the case of random rough surfaces, which can be described statistically. The derivations of classical asymptotic models (Kirchhoff-tangent plane approximation, small perturbation method, etc.) are given for calculating both the scattered field and the statistical average intensity. Their validity domains are given theoretically and are illustrated by comparison with a reference numerical method (Method of Moments). Coherent and incoherent components of the normalized radar cross section (NRCS) are both analyzed.