The St. Louis Center for Inquiry in Science Teaching and Learning (CISTL) combines a focus on research into science teaching and learning with a focus on professional development and support needed to bring inquiry-based teaching and learning into K-12 science education in both formal and informal settings. Joining together in this effort are three informal science institutions, two universities, five school districts, one community college system and the Association of Science-Technology Centers (ASTC). CISTL will address the full continuum of science educators -- those entering the field, those in the field and those retooling from one area of expertise to another. Their research agenda focuses on the effect of varying types of collaboration on professional development and the interfaces among the collaborators (education and scientific; formal and informal). A diagnostic tool for assessing strengths and weaknesses in science and inquiry backgrounds will be developed for teachers and other science educators. In addition, the project will create a synergy between research and practice through research based in practice, practice based on research and the translation of results into practical suggestions for educators.