Conventional light microscopes have long been limited in resolution to around 200 nm in width and 500 nm in depth due to the nature of light diffraction. Resolution at much greater magnifications would have required the use of the electron microscopes. However, with recent methodological discoveries in optics such as Stimulated Emission Depletion (STED), Structured Illumination Microscopy (SIM), Stochastic Optical Reconstruction Microscopy (STORM), Photoactivated Localization Microscopy (PALM), Fluorescence Photoactivation Localization Microscopy (FPALM), resolution down to tens of nanometers in width and a few hundred nanometers in depth is now possible with light microscopy. A new class of “Super-Resolution” microscopes is now available, each tailored to suit a wide variety of imaging applications, such as 3D fluorescence imaging, live cell imaging, colocalization, and even in vivo imaging.