In study after study, three priorities appear to make a difference to the principal's view of the teacher-librarian. First, teacher-librarians who collaborate with classroom colleagues make a difference to literacy and student achievement; those who don't, don't. Second, teacher librarians who perform leadership roles in the school and in the district are better regarded and better supported. Third, perhaps surprisingly, principals appear to value especially the informal staff development role of the teacher librarian providing short sessions for individuals and interested small groups on new resources, whether print or electronic, and how they might be incorporated in instruction. This article briefly explains these three priorities and offers a website where further information can be found.