Microscopy is a technique for producing visible images of structures or details too small to otherwise be seen by the human eye.
With the exception of techniques such as force microscopy and electron tunnel microscopy, microscopy usually involves the diffraction, reflection, or refraction of radiation incident upon the subject of study.
In classical light microscopy, this involves passing light transmitted through or reflected from the subject through a series of lenses, to be detected directly by the eye or imaged on a photographic plate.
There is also a form of microscopy which works based on a very small probe, and recognizing perturbations of the end of the probe, due to electrical effects.
See also microscope