Perspectives on how to define, operationalize, and measure insight have evolved due to developments in theory, methodology, and technology. Research on insight can be broken into several waves. In the first wave, Gestalt psychologists introduced the concept of insight as a discontinuous form of learning and problem solving that arises from changes in one’s global representation of a problem, in opposition to contemporary associationist views. In the second wave, psychologists examined insight in deliberate contrast with analytical problem-solving and found that insight involves nonreportable mental operations leading to a discrete, all-or-none availability of representational change. In the third wave, thanks to advances in behavioral methods and neuroimaging technology, cognitive neuroscientists began to examine how insight occurs in the brain with the goal of studying the neural states that co-occur with and precede insight to better understand its cognitive mechanisms. The advances made during these initial waves enabled the proliferation of research on insight over recent decades and inspired new discoveries. This chapter provides a brief retrospective on the first two waves of insight research and a more in-depth overview of the third wave of research on the cognitive neuroscience of insight, and ends by discussing current and future directions in insight research