This book provides new methods and advanced experimental techniques for the design, analysis, and testing of highly flexible deployable/inflatable structures (HFSs), including systematic nonlinear modeling approaches, newly developed geometrically exact structural theories, numerically exact solution methods, fully nonlinear finite element techniques, and non-contact techniques for static and dynamic testing. Chapter 1 summarizes characteristics of HFSs, points out challenging modeling and analysis issues, and presents state-of-the-art measurement systems that are appropriate for testing HFSs. Chapter 2 presents the fundamentals of structural mechanics to prepare the reader for geometrically exact modeling of HFSs. Chapter 3 presents the fundamentals of nonlinear finite element analysis and the multiple shooting method of solving nonlinear ordinary differential equations for numerically exact solutions. The book then proceeds in treating different structural systems from simple 1D systems (trusses and cables in chapter 4, and beams in chapter 5), to 2D systems (plats and shells in chapter 6, and membranes in chapter 7), and to complex systems (smart structures in chapter 8).The author uses the lowest possible level of mathematical complexity as possible to convey concepts.