Research shows that an important step in the development of readers is having access to books. Steven Krashen, in "The Power of Reading," cites multiple studies that demonstrate access to books is crucial in developing strong readers: "the richer the print environment, the better the literacy development." Limiting access runs counter to research and to the American Association of School Librarians' "Standards for the 21st-Century Learner." Librarians need to oversee book circulation, but the author contends that they are not really promoting reading and literacy development if their library environment values neat shelves and prompt book returns as more important than regular access to books.