Electron Microscopy (EM) is used for seeing otherwise invisible worlds of microspace (1 m = 10-6 m) and nanospace (1 nm = 10-9 m). By using a beam of high energy electrons, EM reveals levels of detail and complexity inaccessible by light microscopy (LM). EM provides the user with several advantages over LM, of which spatial resolution is perhaps the most eye-catching and appealing. Spatial resolution can be defined as the smallest distance between two closely opposed points, at which they may be recognized as two separate entities. The best lateral resolution possible in a LM is about 200 nm, whereas an EM can resolve features in the range of a couple of nm down to sub nm level, depending on which kind of EM is used.