We have seen a great increase in the amount and types of research into metacognition since Flavell first put out the call for researchers to investigate metamemory (Flavell, 1971). Metacognition has been explored in a wide range of areas and positive effects of developing metacognitive awareness have been reported across most academic subjects, in health related areas, in social relationships, in law and other social science fi elds, and in all age groups. Metacognition is linked to big questions around intelligence, consciousness and emotions. A great deal of theoretical work has delineated and described the different components of metacognition, how they work together, and their effect on cognitive processes. From its initial conceptualisation, metacognition was seen as incorporating both declarative knowledge, referred to as metacognitive knowledge, and procedural knowledge aimed at monitoring and controlling thinking. Procedural metacognition has also been referred to as metacognitive skills. Many other terms are used to refer to different kinds of metacognitive processes, so we might refer to meta-strategic knowledge to indicate knowledge about strategies and ability to select the most appropriate strategy. Terms such as meta-knowing have been used to refer to the development of knowledge about sources of knowledge and understanding of epistemology. Metacognitive awareness is often used to refer to knowledge about when and how to use metacognitive knowledge. Researchers from different branches of psychology and social sciences may use the terms slightly differently, but there is a growing consensus that metacognition is important for self regulated learning, learner autonomy and educational achievement.