Several methodologies have been developed over the past several years for super-resolution fluorescence microscopy including saturated structured-illumination microscopy (SSIM), stimulated emission depletion microscopy (STED), photoactivated localization microscopy (PALM), fluorescence photoactivation localization microscopy (FPALM), and stochastic optical reconstruction microscopy (STORM). While they have shown great promise for biological research, these techniques all have individual strengths and weaknesses. This review will describe the basic principles for achieving super resolution, demonstrate some applications in biology, and provide an overview of technical considerations for implementing these methods.