Active vision refers to the exploration of the visual world with rapid eye movements, or saccades, guided by shifts of visual attention. Saccades perform the critical function of directing the high-resolution fovea of our eyes to any point in the visual field two to three times per second. However, the disadvantage of saccades is that each one disrupts vision, causing significant visual disturbance for which the brain must compensate. Exploring the interaction of vision and eye movements provides the opportunity to study the organization of one of the most complex, yet best-understood, brain systems. Outlining this exploration also illustrates some of the ways in which neuroscientists study neuronal systems in the brain and how they relate this brain activity to behavior. It shows the advantages and limitations of current approaches in systems neuroscience, as well as a glimpse of its potential future.