This volume deals with the significance of the apoblast and the intracellular matrix in cell to cell signaling in plants and animals. Researchers working on human, animal and plant systems discuss their own specific problems. The dynamics of the cell surface as related to both growth and development, as well as to the transduction of environmental signals and the feed-back from genetic information to the cell surface are comprehensively covered. Special emphasis is laid on experimental models, their applicability and discussion of possible directions for future research.