Picture books, when used thoughtfully and artfully, can teach theories to graduate students in literacy and foreign language education. In this article, the authors described how a pair of picture books is used to teach Vygotsky's "Zone of Proximal Development" and Krashen's "Input Hypothesis" in the fields of literacy education and applied linguistics. The authors first introduced the theoretical foundation and rationale of using picture books as paired texts to teach educational theories. Then, from a macroperspective, they described the procedures of designing a class activity with paired picture books. Next, they provided language teachers and educators with a specific sample in which materials, objective, and specific instructional steps are clearly listed. In the end, the authors explained how the article contributes to the field from three perspectives: first, it offers a helpful strategy to language educators who make instruction of theories to graduate students easier; second, it provides insights to language and content area teachers on teaching across the curriculum by using picture books; third, it suggests how teachers can pair other learning mediators with picture books to improve student learning.