The articles developed for this special issue of Mathematical Thinking and Learninggrew out of a series of two meetings held at Vanderbilt University in November 1999 and Northwestern University in September 2000. As a group, the six articles in this special issue have the potential to help us reframe issues of equity in mathematics education and to enrich understandings of the process by which "diverse" learners experience mathematics education. Some of these articles are theoretical in orientation and offer insights to how the sociocultural approach to equity in math education might be developed. Other papers rely on close analyses of mathematical learning in and out of the classroom to understand the construction of "equity" at the micro-level of social interactions. In sum, the articles that make up this special issue take the social and cultural worlds in which mathematics is learned to be central to the understandings of the dynamics of equity. The editors hope that the understandings of equity, diversity and mathematical learning continue to evolve and that this special issue will serve to spark thought, controversy, debate, and further research on this critically important topic.