A major goal of Library Power was to increase the collaboration among classroom teachers and librarians, The research reported in this article supports the conclusion that Library Power was successful in achieving this goal, Analysis of data from over 400 schools (including collaboration logs completed by librarians and questionnaires completed by principals, librarians, and teachers) shows that participation in Library Power increased the percentage of schools where teachers and librarians collaborated to plan instruction and to develop the library collection. Library Power also apparently increased the percentage of teachers who collaborated with the librarian in schools where collaboration already existed. Collaborative logs supported the conclusion that library skills were integrated into the curriculum at all grade levels.