An update to the original 1992 publication, this two-volume set unites current research to provide new conceptualizations of research problems, and to suggest possible research programs to move the field forward. In studying the existing research, the authors found that the community has maintained its focus on problems of learning, teaching, teacher education, assessment, technology, and social and cultural aspects of mathematics education, while some new areas of interest have emerged or been expanded. This set allows educators to step back and look at each of these areas to see where mathematics education research has been and where it should be going to enable the field to answer the questions about education that practitioners, policy makers, and politicians are asking.