This guide is intended to help you as you work with teachers, preparing them to use Stuff that works! (or City Technology) materials in their classrooms. Some teachers, already experienced in science inquiry and/or other varieties of reform-based pedagogy, will be able to use the City Technology guides without further assistance. Most teachers, however, will need some formal professional development to facilitate the use of the new ideas and activities. The Guide includes general information about professional development, the structure of our workshops and the reasoning behind each component, ideas about how to handle the “thorny issues” that typically arise, and a complete description of the six Stuff that Works! workshops, including one introductory workshop covering all five topics.