This policy brief presents a professional consensus regarding the dimensions of teaching quality and the issues that need to be addressed if California is to ensure high quality instruction for all students. It is based on the work of an expert panel of education stakeholders who reviewed research, met with outside experts, and discussed in depth the issue of teaching quality. The brief summarizes current research, as well as the panel's definition of and perspective on teaching quality. First, the brief discusses prevailing perspectives on teaching quality and related research. Then, the brief discusses the panel's conclusions regarding the development of a quality-based teacher development system. (Contains 27 notes.)