There has been a great interest in Guided waves which have wide applications in optical fibers, phase shifters in optics and telecommunications. This book describes the propagation characteristics of nonlinear electromagnetic surface waves (modes) along the boundary of a linear gyromagnetic medium and various nonlinear dielectric structures . The dispersion relation for TE and TM surface waves (modes) guided by a lateral antiferromagnetic/ nonmagnetic superlattices (LANS) of frequency dependent permeability tensor and a nonlinear dielectric cladding or nonlinear magnetic cladding has been investigated. Also the stability which has been investigated and reported here may provide new opportunities for the design of microwave-photonic devices such as receivers of radio telescope, reflection and transmission filters.