This book summarizes the exciting breakthroughs made in the understanding of the exocytotic pathway. The following aspects are covered: the molecular identification of proteins responsible for polypeptide translocation across the ER membrane, functional establishment of several soluble proteins in membrane fusion, the proposal of SNARE hypothesis for the specificity of vesicle docking/fusion, the molecular and functional elucidation of COPI and COPII protein coat of transport vesicles, functional characterisation of several classes of GTPases in protein trafficking, the identification of several sorting/targeting signals for precise intracellular localisation, molecular and mechanistic elucidation of neurotransmitter release, and genetic as well as biochemical identification of many other proteins.