All work to improve the quality of professional development must begin with one simple assumption: Teaching is an incredibly complex profession that draws on a wide set of intellectual and emotional skills. Even the best teachers need to continue to learn and improve their practice, and many are willing to do so. The bottom line is that all teachers--all educators--grow from professional learning experiences that sharpen their practice. However, the teaching profession in America is at a crossroads. Designed more than a century ago, in many ways teaching remains stuck in an outmoded and inadequate system of preparation and improvement. States, districts, and the federal government spend $25 billion annually on support services to develop teachers and leaders. But most of what is spent has neither improved teaching nor benefitted teachers or students. In this article, U.S. Secretary of Education Arne Duncan calls on education leaders to rethink how they support teachers to offer the world-class education children deserve.