The Lower School Library's mission is to instill in each student a lifelong love of learning and reading. The Cooper Library is one of the largest and most technologically-advanced libraries in the state. The library's collection includes over 28,000 titles, and the facility includes a classroom, story room, computer lab, research classroom, and a tutoring room. Two librarians and three research teachers provide instruction and a variety of activities which support and enhance the curriculum of the Lower School.
Each fall, the Cooper Library hosts a visiting author. Past visits have included nationally renowned and award-winning authors and illustrators such as Kenn Nesbitt, Janet Stevens, Susan Stevens Crummel, Carmen Deedy, Jim Arnosky, Avi, Brian Floca, Floyd Cooper, Pamela Duncan Edwards, Henry Cole, Steven Kellogg, Jerry Pallotta, Richard Peck, Brian Pinkney, Jack Prelutsky, Robert San Souci, and David Schwartz.