This book presents navigation solutions in the regime of reactive controllers that take into account the limitations in sensing and computation abilities as well as the nonholonomic motion of the robot in environments cluttered with moving and static obstacles. Since the objective of the navigation can be divided into target reaching and collision avoidance, the reactive controllers are designed as switching controllers between the two modes. The resulting system exhibits sliding-mode behavior. The major contribution of the book lies in the justification of the global convergence of the system using the proposed controllers via rigorous mathematical analysis under certain assumptions about the geometry of the problem.