In order to support teacher quality in mathematics and science—powerful, content-specific staff development should be designed that is data-driven and evaluated, and is based on using ideas that work and knowing how educators learn. These themes provide the framework for this chapter and serve as a launch pad for a discussion of what is important in professional development today, what the key issues and trends are, and how we can continually improve the planning and implementing of effective professional learning experiences for educators that have positive results for student learning. Examples of the best ideas in the field of professional development today are drawn from the book, Powerful Designs for Professional Development (Easton 2004).