The seminar is the continuation of the previous one on the subject of the theory of classical elasticity. It will be focused on: the hypotheses and the two description methods of the theory. We will see that the hypotheses impose some restrictions on the characteristic length scales, time scales, the type of physics, the properties, the geometry, etc. of the sample under study. We will make a clear distinction between the two description methods of the deformation phenomenon, Lagrangian/material and Eulerian/spatial.