In August 2008, the National Council of Teachers of Mathematics (NCTM) brought together approximately 60 mathematics education researchers and practitioners for a 4-day working conference. During this working conference, the participants analyzed over 350 mathematics education practitioner-generated questions in seven areas: assessment, curriculum, equity, student learning, technology, teaching, and teacher preparation/professional development. Their work produced a set of questions that communicate practitioners' needs for research that would affect their practices. This document is the result of the working conference. The purpose of this document is to: (1) emphasize the need for communication and collaboration between practitioners and researchers around issues that are important to practitioners; (2) make practitioners' research needs, both as initiators and consumers of research, explicit to the mathematics education research community; (3) promote a set of research-guiding questions that focus researchers' attention on critical problems of practice; and (4) urge funding agencies, policymakers, and other mathematics education stakeholders to support research that is grounded in practitioners' problems of practice.