In this book, the authors concentrate on the surface Plasmon (SP) waveguide configurations ensuring nanoscale confinement and review the current status of this rapidly emerging field, considering different configurations being developed for nanoscale plasmonic guides and circuits. Both fundamental physics and application aspects of plasmonics are reviewed in detail by the world's leading experts. A unique feature of this book is its strong focus on a particular subfield of plasmonics dealing with subwavelength (nanoscale) waveguiding, an area which is especially important in view of the explosively growing interest in plasmonic interconnects and nanocircuits.