Neurotransmission is the fundamental biological process by which neurons communicate with each other and with target cells, predominantly via chemical or electrical signals transmitted across synapses. As an academic concept and research field, it investigates the intricate molecular, cellular, and systems-level mechanisms governing the synthesis, release, diffusion, binding, and inactivation of neurotransmitters, alongside the structure, function, and plasticity of synapses. Key characteristics explored include the diversity of signaling molecules, receptor pharmacology, ion channel dynamics, and the regulatory processes that modulate synaptic strength and connectivity. Its significance is foundational to understanding the functional architecture of the nervous system, the basis of cognition, behavior, and physiological regulation, and is indispensable for identifying targets for therapeutic intervention in neurological and psychiatric disorders.