In this article, I introduce a framework--the What, Who, and How of mathematics--that emerged from studying my teaching of prospective teachers and their views of the social and political dimensions of mathematics teaching and learning. The What, Who, How framework asks us to consider What messages we send about mathematics and the world, Whose perspectives are represented in mathematics, and How mathematical concepts and our world are related. I situate each aspect of the framework in the literature on social justice and critical mathematics and provide examples of prospective teachers' views. The What, Who, How serves as a tool to understand prospective teachers' views, to navigate a broad range of literature on social justice mathematics, and a means of informing the practice of teachers and teacher educators.