Lighting is an indispensable component of the interior environment, especially in a teen library that proper lighting will provide a better reading experience. To improve interior light condition for teen’s activities and maximize natural light to save energy, optical lenses and reflective materials are wisely applied within the design. Concave lenses are applied around windows to maximize natural light. Adjustable angle of the window hangings are designed to adapt to different intensity of light in different seasons. Concave form is applied on lighting features as well. The curved form, reflective material, adjustable height, and embedded spotlights allow natural light and artificial light to bounce around and within the space to effectively use light resources. In addition, based on natural lighting distribution within the site, each program is assigned to certain location according to its demand of natural light. For instance, reading area is assigned close to south facing windows to harvest most natural light; multi-purpose room is assigned in the center of the library because of its least demand of natural light. Furthermore, engaging and having control of elements in the interior space will attract teens to come to the library. Revolving furniture and partitions encourage teens to activate and change the furniture, as well as enabling different scaled transformations to adapt to different programs. Pivoting and sliding partitions are used to create a transformable, multi-purpose room. When the partitions are closed, the room will become a pre-college classroom, which also serves as a group meeting room, and conference room. When the partitions are open, the “room” will vanish, the library will be turned into a movie theater or music hall. When the room is open, stackable chairs and foldable work desk will be stored in the storage room, which is behind the projection screen. Pivoting benches encircle pivoting bookshelves, which implies knowledge is the pivot center of our society. The pivoting benches can be either for individuals or formed into small groups, depending on the orientation of adjacent benches.