The Carnegie Foundation for the Advancement of Teaching is a nonprofit, operating foundation with a long tradition of developing and studying ways to improve teaching practice. For the past three years, the Carnegie Foundation has initiated three different Networked Improvement Communities (NICs). The first, Quantway, is addressing the high failure rate of students in developmental mathematics. Eight community colleges in three states are part of this network, as are several intermediary organizations whose work focuses on curriculum, faculty development, and student support. The second NIC, Statway, is also focused on community colleges. It involves 19 colleges in five states and is a pathway to college statistics. The third NIC, Building a Teacher Effectiveness Network (BTEN), is working on teacher quality, specifically on developing and retaining teachers in the first three years of teaching. The BTEN network members include the Carnegie Foundation, the Institute for Healthcare Improvement (IHI), the American Federation of Teachers (AFT), New Visions for Public Schools (NVPS), the Austin Independent School District (AISD), and the Baltimore City Schools (BCS). Carnegie staff act as the primary facilitators of the work, guiding the improvement process. IHI and AFT also help facilitate the improvement work. AISD, BCS, and NVPS are sites that test ideas. This case study discusses the partnership and is organized into the following sections: (1) History; (2) Nature of the Partnership; (3) Challenges; and (4) Benefits. [This case study is a supplement to "Research-Practice Partnerships: A Strategy for Leveraging Research for Educational Improvement in School Districts," ED568396.]