Engineers and researchers concerned with the problems of thin-walled structures have a choice of books on shell theory. However, the almost exclusive concern of these books are shells designed for maximum strength and stiffness. Shells which are designed for maximum elastic displacements (flexible shells) have been used in industry for decades, but are largely ignored in shell-theory books due to tradition and to the wide variety of shapes and problems involved.This book presents the general theory of elastic shells and the deformation inherent in flexibility. For the analysis of stability of the two-dimensionally variable large elastic deformations, a local approach is developed.The specialized theory is then applied to the basic problems of flexible shells - tubes, open-section beams and shells of revolution. The results of parametric studies are presented in numerous graphs.