Near field microscopy has proved to be an efficient tool to break the Rayleigh criterion of resolution. A high spatial frequency object generates evanescent waves if illuminated by propagating or evanescent waves. The generated, non- detectable local field may partly be turned into a propagating wave by a small scatterer, which can already be detected, reflecting the spatial structure of the object. This principle is used in different forms in sub-wavelength resolution microscopy down to the nanometer scale. If the scatterer is the tip of a scanning tunneling microscope (STM), the evanescent field-tip interaction leads to the change of the tunneling current, resulting in a special type of the near field microscope. The evanescent field could be that of surface plasmon oscillations (SPO). The state of art of near field microscopy, and as an example the SPO-STM case, is discussed in detail.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.