Confocal microscopy is a rapidly evolving technique which is solving problems in the biological and material sciences. This tutorial focuses on the confocal microscopy of living cells. Both in vivo and in vitro applications of confocal microscopy will be reviewed. Applications of confocal microscopy of the eye will illustrate the concepts. Fluorescence and back scattered confocal microscopy are critically reviewed. A bibliography on confocal microscopy is given to aid the users of this technique.Books (Optical Theory, Image Formation, Fluorescence Techniques) •Theory and Practice of Scanning Optical Microscopy, (eds. T. Wilson, C. Sheppard), Academic Press, London, 1984.•Confocal Microscopy, (ed. by T. Wilson), Academic Press, London, 1990.•Handbook of Biological Confocal Microscopy, (ed. J.B. Pawley), Plenum Press, New York, 1989.•New Techniques of Optical Microscopy and Microspectroscopy (ed. R.J. Cherry), CRC Press, Inc., Boca Raton, Florida, 1991.•Noninvasive Techniques in Cell Biology, (eds. J.K. Foskett, S. Grinstein), Wiley-Liss, New York, 1990.