This monograph is concerned with the development and implementation of nonlinear mathematical techniques for feedback control and shape design of robot manipulators whose links have considerable structural flexibility. Several nonlinear control and observation techniques are studied and implemented by simulations and experiments in a laboratory setup. These techniques include integral manifolds in singular perturbation theory, nonlinear input-output decoupling, nonlinear observers and sliding control. The study of dynamic properties and control techniques for flexible-link manipulators can also be a framework for designing the mechanical shape and material of these systems such that improved properties can be achieved in order to facilitate the control problem. Therefore, structural shape