InBucklingenergy methods the bifurcational buckling analysis of thin-walled composite lightweight structures, mathematically rigorous solutions can only be specified for a few idealized structures under certain boundary conditions and load cases. Therefore, the vast majority of engineering applications rely on approximate solutions. Common approximation methods are generally based on statements about the energy balance of the structure under consideration. This chapter is dedicated to an overview of such so-called energy methods. In addition to the presentation of the analysis methods, some typical problems that can be suitably treated with the help of energy-based methods are also discussed.