High-stakes educational testing is a global phenomenon which is increasing in both scale and importance. Assessments are high-stakes when there are serious consequences for one or more stakeholders. Historically, tests have largely been used for selection or for providing a ‘licence to practise’, making them high-stakes for the test takers. Testing is now also used for the purposes of improving standards of teaching and learning and of holding schools accountable for their students’ results. These tests then become high-stakes for teachers and schools, especially when they have to meet externally imposed targets. More recent has been the emergence of international comparative testing, which has become high-stakes for governments and policy makers as their education systems are judged in relation to the performances of other countries. In this book we draw on research which examines each of these uses of high-stakes testing. The articles evaluate the impact of such assessments and explore the issues of value and fairness which they raise. To underline the international appeal of high-stakes testing the studies are drawn from Australia, Africa, the Caribbean, Europe, former Soviet republics and North America. Collectively they illustrate the power of high-stakes assessment in shaping, for better or for worse, policy making and schooling. This book was originally published as a special issue of Assessment in Education: Principles, Policy & Practice.