Debates persist over the knowledge needed to teach elementary reading effectively. In one commonly held view verbal ability is what matters most and the best approach to improving teacher quality is to recruit teachers who themselves are good readers. Others argue that teachers need special forms of professional knowledge that differ substantially from common adult reading and verbal ability. These different assumptions about what teachers need to know are directly relevant to whether teaching reading demands specialized professional knowledge and they have lead to radically different policy recommendations for both teacher preparation and induction. This study presents preliminary evidence that elementary reading teachers can hold a special knowledge of language, text, and reading process that differs substantially from common reading and verbal ability. Implications for the measurement and study of teacher quality and related implications for teacher evaluation and teacher development are discussed.