Over the last few years, artificially structured media, referred to as metamaterials, have attracted much attention due to their extraordinary electromagnetic responses not found in naturally occurring materials. This book in particular focuses on studying and harnessing the possibilities opened up by two emerging classes of metamaterials: plasmonic materials and dispersion-engineered materials. The former has the capability to confine optical fields at nanoscales beyond the diffraction limit, while the latter has the capability to dramatically slow down electromagnetic wave propagation. The analysis of these metamaterials is presented in detail using sophisticated full-wave modeling techniques. New numerical algorithms for solving Maxwell equations in these metamaterials are also introduced to achieve a significant increase in computational efficiency. The algorithms and analysis presented here should especially be helpful to professionals in the fields of microwaves, optics, and materials science and engineering.