Working closely with educators is one of the most effective strategies for reaching students in classrooms across the nation. PRI began this approach under Dr. Allmon’s leadership in the 1990s, considering how best to make an impact in K-12 STEM education with a small staff, but considerable expertise and resources. We now implement a wide range of innovative programs to develop new approaches and materials for teacher professional development. These programs focus especially on Earth system science, biological evolution, and climate and energy. PRI also collaborates with other organizations. For example, we offer workshops with the Cornell Institute for Biology Teachers, and with the New York Academy of Sciences, which provides support for graduate student mentors doing afterschool programs in New York City schools. We also offer workshops and resources at national conferences, such as the annual meetings for the Geological Society of America, National Science Teachers Association, Science Teachers Association of New York State, and North American Association for Environmental Education.