The new edition of this popular book brings together experts in the field of Systems Neuroscience to present an overview of the area. Topics covered include how different neural circuits analyze sensory information, form perceptions of the external world, make decisions, and execute movements; how nerve cells behave when connected together to form neural networks; the relationship between molecular and cellular approaches to understanding brain structure and function; the study of high-level mental functions; and studying brain pathologies and disease. Among the topics covered in the new edition are artificial intelligence-assisted computational neuroscience for deciphering neural networks, spatial transcriptomics single cell sequencing, and exome/whole genome sequencing for understanding brain disorders in human genetics. The best way to study the brain, the most complex organ in the body composed of 100 billion neurons with trillions of interconnections, is with a systems biology approach.