Book excerpt: Neurons in the nervous system organize into complex networks and their functions are precisely controlled. The most important means for neurons to communicate with each other is transmission through chemical synapses, where the release of neurotransmitters by the presynaptic nerve terminal of one neuron influences the function of a second neuron. Since the discovery of chemical neurotransmission by Otto Loewi in the 1920s, great progress has been made in our understanding of mol- ular mechanisms of neurotransmitter release. The last decade has seen an explosion of knowledge in this field. The aim of Molecular Mechanisms of Neurotransmitter Release is to provide up-to-date, in-depth coverage of essentially all major mole- lar mechanisms of neurotransmitter release. The contributors have made great efforts to write concisely but with sufficient background information, and to use figures/diagrams to present clearly key concepts or experiments. It is hoped that this book may serve as a learning tool for neuroscience students, a solid reference for neuroscientists, and a source of knowledge for people who have a general interest in neuroscience. I was fortunate to be able to gather contributions from a group of outstanding scientists. I thank them for their efforts. In particular, I want to thank Dr. Erik Jorgensen who offered valuable suggestions about the book in addition to contrib- ing an excellent chapter. I thank US National Science Foundation and National Institute of Health for their supports.