The relationship between practice and explanation is a dynamic one; explanations are needed to make sense of experience and inform practice. Some explanations will be your own, to be tried and tested against the theories of others, often more experienced teachers and educators. At other times you may use directly the explanations of others. Explanations in turn generate working theories, responsive to practice and experience. Theory is important; it provides a framework in which to understand the complex world of the classroom and to direct further research into improving the quality of learning. It provides, too, a reference point against which to judge change and development, both of yourself and schools. It is the encompassing of these ideas, the interplay of theory and practice, which underpins the notion of the reflective practitioner.