The superior colliculus ('colliculus'), or optic tectum, is a highly conserved area of the brain that is critical for the organization and control of attention and orienting behaviors. It lies at the top of the midbrain and our understanding of its structure and function is based on work from many vertebrate species including: lampreys, fish, amphibians, reptiles, birds, rodents and primates. In each of these species, its well defined set of visual inputs and strong links to motor functions have provided much insight into how the circuits of the brain link sensory inputs with behavior to help animals interact with the world. Although often thought of as a primitive structure guiding reflexive and instinctive behaviors, the colliculus is well connected with the rest of the brain and plays an important role in a diverse set of important behavioral and cognitive functions.