The rare book library which is proposed is for scholarly research along with a conservation laboratory for early American printed manuscripts and documents. The site is located between Downtown and North End, Boston. Currently, North End Branch of the Boston Public Library is located at this site. Downtown is the central business district of Boston. North End is the city’s oldest residential community. The contrast between these urban fabric is very strong. The new rare book library is a microcosm of Downtown and North End. The density of these urban fabrics is reinterpreted as a program distributor for the library. The West of the site is allocated for large and public programs; main entrance, café, shop, and common space. The east of the site is used for small and more private programs; book shelving and carrels. Book cases are located is dark space in the library’s spine, while carrels are located at the glass boxes which extruded from the spine for maximum natural light.