As human beings we have a unique capacity of making meaning of information we take in and forming representations of our mental states. In doing so, we label our emotions and think about the desires and intentions of ourselves and others. The process of thinking about thinking, defined in simple terms, is known as metacognition. It is a uniquely human capacity, one that is necessary for a successful adaptation in our dynamic social world. As awareness of the process of metacognition has grown, so have considerations of its deficits in relationship to various forms of psychopathology, such as autism. In the 1990s, the possibility of deficits in the metacognitive capacity of adults with serious mental disorders was examined, which led to an explosion in metacognition literature. These efforts involved a variety of research methods and foci.