The development of advanced optical structures has enabled tremendous control over the propagation and manipulation of light waves. At the forefront of these advances is the development of micro- and nanostructured optical devices that have dimensions smaller than the wavelength of light. In particular, the engineering of light localization, optical dispersion and plasmonic fields in complex optical media has the potential to boost the scaling of optical technologies below the diffraction limit, opening unprecedented opportunities for basic and applied research. This book bridges three closely related research fields of nanoplasmonics, metamaterials and light localization in complex media. The goal is to share recent progress, identify critical problems and provide promising solutions for the next generation of photonic functionality. Topics include: metamaterials and superlenses; metamaterials; and optical nanoantennas and decay engineering.