Barry Stroud examines what a person would have to do and believe in order to reach the conclusion that everyone's perceptions and beliefs about the colour of things are "illusions" and do not accurately represent the way things are in the world as it is independently of us. It is not simply a question of the consistency of a certain state of affairs, but of whether this is a possible outcome of an inquiry a human being could actually carry out. Arguing that no such conclusion could be consistently reached, Stroud finds that the conditions of a successful unmasking of colour cannot all be fulfilled. The discussion extends beyond colour to present a serious challenge to many other philosophical attempts to discover the way things really are.