The text demonstrates how professional insight emerges as teachers identify the elements that supported their understanding during their own learning. In this paradigm, professional awareness derives from the practitioner interrogating their own learning and identifying implications for their teaching of science. The book draws on a significant body of critically analysed empirical evidence collated and documented over a five-year period involving large numbers of trainee and practising teachers. It concludes that it is essential to ‘problematize’ subject knowledge, both for learner and teacher. The book’s theoretical perspective draws on the field of cognitive psychology in learning. In particular, the role of metacognition and cognitive conflict in learning are examined and subsequently applied in a range of contexts. The work offers a unique and refreshing approach in addressing the important professional dimension of supporting teacher understanding of pedagogy and critically examines assumptions in contemporary debates about constructivism in science education.