The book presents the method of analysis of the stress-strain state of thin-walled structures at the stages of manufacture and operation. It is based on the model making use the concept of a yield surface separating the ranges of elastic and elastic-plastic deformations and regularities of plastic deformation and strain hardening of a material under simple and combined loadings. In this case, the allowance is made for strain hardening either of the material of a structure or strain indicators attached to its surface. The examples of employment of the method in evaluating of the stress-strain state of cylindrical shells of different designations are given. The method is useful especially when the processes of loading and measuring of stresses and strains are separated in time. Such necessity arises particularly in the cases of establishment of reasons for origin of emergency situations.