This Handbook presents an overview and analysis of the international `state-of-the-field' of mathematics education at the end of the 20th century. The more than 150 authors, editors and chapter reviewers involved in its production come from a range of countries and cultures. They have created a book of 36 original chapters in four sections, surveying the variety of practices, and the range of disciplinary interconnections, which characterise the field today, and providing perspectives on the study of mathematics education for the 21st century. It is first and foremost a reference work, and will appeal to anyone seeking up-to-date knowledge about the main developments in mathematics education. These will include teachers, student teachers and student researchers starting out on a serious study of the subject, as well as experienced researchers, teacher educators, educational policy-makers and curriculum developers who need to be aware of the latest areas of knowledge development.