The nervous system is the primary mechanism for regulating and controlling the actions as well as communicating the sensory information within the body. It consists of the spinal cord, brain and a complex network of nerves. All mental activities such as memory, thought and learning are centered on the nervous system. This system relays messages between the body and the brain. The nervous system is divided into two parts which include the central nervous system (CNS) and the peripheral nervous system (PNS). The spinal cord and brain make up the CNS whereas the autonomic and somatic nervous systems make up the PNS. The majority of multicellular organisms have nervous systems but their complexity varies substantially. This book explores all the important aspects of nervous system from a molecular biological perspective. It is appropriate for students seeking detailed information in this area of study as well as for experts. Different approaches, evaluations, and advanced studies on this topic have been included in this book.