The library was designed with the intention of serving as an anchor to community of San Juan and other counties in Puerto Rico while providing the users learning opportunities in a comfortable and versatile space. Diving deep into the purpose of book margins I thought of how much it could reflect in a floor plan as a concept. Margins are not just a simple empty border; they make books perfectly proportioned while making the user focus in the content of the book. The concept "Margins" is incorporated in the space planning, furniture arrangement, and architectural elements.