Plasmodesmata are minuscule plasma corridors between plant cells which are of paramount importance for transport, communication and signalling between cells. These nano-channels are responsible for the integrated action of cells within tissues and for the subdivision of the plant body into working symplast units. This book updates the wealth of new information in this rapidly expanding field. Reputed workers in the field discuss major techniques in plasmodesmatal research and describe recent discoveries on the ultrastructure, the functioning and the role of plasmodesmata in intracellular transport and communication, in cell differentiation, plant development and virus translocation.