The synapse is a fundamental subcellular structure in the brain connecting neurons with each other. It transmits information from one neuron to another and is also involved in data processing and storage. The synapse is the site where neurons communicate with each other. A synapse is a small gap that physically separates neurons. This book is a comprehensive and detailed overview of the synapse with emphasis on the glutamatergic synapse. Most chapters relate functional aspects to molecular mechanisms. This approach provides a sense of which mechanisms are characterized on both the functional and structural level and can be considered firmly established. The chapters on basic physiological mechanisms are complemented by several chapters on the role of the synapse in pathological states.