This article is presented by four librarians who have come together as a creative team at Ethical Culture School in New York City. As elementary school librarians, their goal is to develop and support curriculum where children's developmental needs are given central importance. By putting the thinking, interests, information needs, and the information-seeking behavior of children first, they aim to eliminate the barriers that young users face in accessing and using their collections to their fullest potential. In this article, the authors describe Metis, an alternative they created to the Dewey Decimal Classification system. Their goal was to encourage productive independent browsing by children as well as allow for successful catalog searching by elementary students, thereby helping to keep libraries relevant in today's ever-changing technological world. They conclude that when a system is easy to understand, as Metis is, students learn how to categorize topics and navigate the system; this ability to categorize is an invaluable skill that they will apply to countless future situations.