At a time when test results can be everything, high scores may be pursued whatever the cost. Perhaps more than many would admit, the cost is a lack of understanding. This text describes why understanding is worthwhile and what understanding means, particularly in the subjects commonly taught in schools, colleges and higher education. It draws on research to provide a framework of strategies known to support the understanding processes. Learners may fail to understand for a variety of reasons. Why this happens and what can be done is discussed, including inappropriate conceptions of learning amongst teachers and learners, matters to do with motivation, the assessment of understanding, and what learners can do to help themselves. Unlike many books on learning, this text focuses directly on the problem of understanding and how to support it. It recognizes and illustrates the variation of understanding in different contexts and provides a framework for thinking about understanding and how it might be fostered. Understanding can be an early casualty in teaching and learning and an aim of this book is to make it a central and enduring concern at all levels of education.