Evanescent waves play a growing role in many different areas, such as guided optics, optical-fiber couplers, integrated optical elements, internal reflection spectroscopy, atom optics, dark-field microscopy, scanning tunneling optical microscopy, microaperture microscopy, and apertureless microscopies. This book describes the near field of an object through the role of the evanescent field in these areas of research. Intended as a reference for scientists and as an introduction at the graduate level.