This chapter provides a foundational overview of the nervous system, essential for understanding the neurobiological bases of maladaptation. It begins by detailing the structure and function of the neuron, the system’s primary building block, and describes how action potentials and synaptic transmission occur. The functions of glia cells are briefly introduced. This chapter then outlines the organization of the nervous system into the peripheral and the central components, giving a brief anatomical description of the major brain divisions (forebrain, midbrain, and hindbrain). The remainder of this chapter focuses on key techniques used to study the neuroscience of maladaptation, such as brain imaging, electrophysiological recording, genetic manipulations, and methods for quantifying gene and protein expression. This discussion highlights how researchers can investigate the neural circuits that drive detrimental behaviors.