Using a Lyapunov-based approach, this book introduces some advanced tools for the stability analysis of nonlinear systems. It first discusses standard stability techniques and their shortcomings and then introduces recent developments in stability analysis that can improve the applicability of standard techniques. Finally, the book proposes the stability analysis of special classes of nonlinear systems, for example time-delayed systems and fuzzy systems. Coverage includes the stability of ordinary time-invariant differential equations and time-invariant systems, as well as the stability analysis of time-delayed systems and fuzzy linguistic systems models.