This chapter reviews briefly some of the fundamental techniques used to study the nervous system in humans and other animals. We begin by considering common methods for measuring brain structure and function, from single-neuron recordings and tissue analysis to whole-brain neuroimaging, touching on some points of clinical relevance. Next, we examine methods for altering brain function experimentally, and consider animal models of psychiatric disease in overview. We examine core ideas in data analysis (including statistics, causality and computational modelling), and conclude with a brief look at key concepts in functional neuroimaging.