The tutorial outlines general ideas and individual particular problems of mechanics of small elastic and elastoplastic deformations of solids. It is shown that some author's solutions can find an application in geomechanics, mining, and construction. Most of the book is devoted to the problems of the mechanics of inelastic deformations. Here, the presentation precedes the outline of the theory of plasticity from the first experiments of Coulomb to endochronous versions of the theory and unconventional (synergistic) models of our days. Considerable attention is paid to the development of the concept of sliding in the theory of plasticity.