The anther tapetum, present in all land plants, is a highly specialized, transient tissue surrounding the (micro-)spores and/or pollen grains during their development. Any tapetum malfunction causes male sterility. The exact knowledge of tapetum form and function therefore is indispensable not only for basic research, but also and especially in plant breeding and plant genetics. In fourteen contributions by reknown experts, a comprehensive account of the various characters and functions of the tapetum is provided, covering the areas of cytology, cytophysiology, biochemistry, tapetum development and function.