The acquisition of literacy, from earliest emergent stages to full fluency with understanding and self-expression in written language, represents a distinct developmental trajectory. Unlike other developmental arenas, achieving literacy combines environmental stimulation and informal interaction in the preschool years with formal school-based instruction in decoding print and reflects the integration of multiple neuronal networks. Skills children acquire along this literacy trajectory powerfully influence life course, from early school achievement to earning potential to lifelong self-expression and civic engagement. Recognizing this, many pediatric health care professionals have incorporated literacy promotion into primary care, often through Reach Out and Read, an evidence-based model (supported by a national network) that provides parental guidance and children’s books at health supervision visits.