The book presents the current understanding of the ultrastructure of specialized intercellular contacts. Particular attention is paid to the ultrastructural changes in cellular contacts within the nervous, immune, and reproductive systems in relation to the performance of specific cellular functions. Based on the author’s own data and results from other morphological, physiological, and biochemical studies, a more comprehensive understanding of the functional significance of intercellular contacts has been achieved. The book is intended for a wide range of researchers in the fields of neurobiology, neuroendocrinology, and the biology of the immune and reproductive systems, as well as for specialists in clinical practice.