This reference on optical imaging techniques covers the field from the basics of the optical microscope to highly advanced techniques such as Förster resonant energy transfer (FRET) and fluorescence lifetime imaging microscopy (FLIM). Using a uniform style and format, it provides an understanding of the underlying principles, so readers can learn the benefits and limitations of each technique described. Topics covered include: optical contrasting techniques, fluorescence and fluorescence microscopes, three-dimensional imaging, the confocal microscope, nonlinear microscopy, advanced fluorescence techniques, and breaking the diffraction limit. Chapters include suggestions for further reading.