Independent Origins and Early Diversification of Neural Systems covers parallel evolution across all 33 phyla in a single reference volume. Using an interdisciplinary approach, this volume addresses the latest research from single-cell genomics to behaviors. The volume discusses the major evolutionary transitions driving the early specification of integrative systems and explains the hypotheses of independent origins of neurons, synapses, and complex brains. Throughout this volume several animal lineages critical for understanding neuronal evolution are highlighted such as comb jellies, sponges, placozoans, cnidarians, and basal metazoans. As a result, the book enables the reader to understand the inherent logic underlying the enormous diversity of neuronal populations and the mosaic or chimeric cellular architectures of virtually every neural system. By deciphering the genealogies of neurons, the book establishes the foundation for natural neuronal classification toward the Periodic System of Neurons with predictive power.