Confocal laser microscopy is a microscopic observation technique patented by Minsk in 1957. Its success is due to the undeniable advantages over traditional optical microscopy including improved image clarity and contrast, greater vertical and horizontal resolution, etc., and above all the possibility to take optical sections of the sample, which allows us to obtain a tridimensional study. This authors of this book provide and discuss new research on the principles, techniques and applications of confocal microscopy.