The Mathematical Sciences Education Board (MSEB) and the U.S. National Commission on Mathematics Instruction (USNCMI) took advantage of a unique opportunity to bring educators together. In August 2000, following the Ninth International Congress on Mathematics Education (ICME-9) in Makuhari, Japan, MSEB and USNCMI capitalized on the presence of mathematics educators in attendance from the United States and Japan by holding a workshop on the professional development of mathematics teachers. This workshop used the expertise of the participants from the two countries to develop a better, more flexible, and more useful understanding of the knowledge that is needed to teach well and how to help teachers to obtain this knowledge. A major focus of the workshop was to discuss teachers opportunities in both societies -- using teaching practice as a medium for professional development.