This book contains an introduction to the fundamental principles of the theory of stability of elastic bodies and structures. Beginning with very basic explanations of stability problems, this book starts with the treatment of systems of rigid beams, before beams under normal force and bending as well as the classical field of beam buckling are treated. For the case of beam buckling, an energetic consideration then follows, which forms the basis for a series of approximation methods. In addition to beam buckling, the stability cases of lateral-torsional buckling and lateral buckling are also of fundamental importance, to each of which a separate chapter is dedicated. This is followed by a discussion of plate buckling, and the book concludes with an introduction to shell buckling. This book is aimed at students at technical colleges and universities, as well as engineers in practice and researchers in the engineering sciences.