Scanning of the visual scene is an important selective process in visual perception. In this article we argue that eye-movement data provide an excellent on-line indication of the cognitive processes underlying visual search and reading. We outline some recent advances from physiological investigations of saccadic eye-movement control before focusing on eye-movement behaviour in visual search and reading studies. We consider factors that can affect the duration of fixations and the choice of saccade targets, emphasising continuities between biological and cognitive descriptions. We discuss different ways of measuring cognitive processing time from an eye-movement record and the relationship between attention and eye movements.