In 1985-86, Robert A.M. Stern Architects studied ways to add on to the St. Paul's School's existing Sheldon Library, designed for the school by Ernest Flagg in 1901. The proposal for the addition would have expanded Sheldon to twice its original size while maintaining its inherent spatial and formal qualities.
When the school's trustees subsequently decided to build a new library, a prominent site at the center of the village-like campus was selected. This design for the Ohrstrom Library forms the boundary wall for two quadrangles: to the south it joins a residential group to create an intimate courtyard; to the north it is the edge of a larger space that is both the symbolic and the actual center of the campus, serving as a counterpoint across time and space to the school's original chapel (1859) and Henry Vaughan's masterly essay in the Gothic, the Chapel of St. Peter and St. Paul (1888).
While H. H. Richardson's Crane Library, Quincy, Massachusetts (1880-82), inspired the plan and the handling of the red brick and Briar Hill stone used for the exterior, the synthesis between traditional form and modern abstraction in the library C. R. Mackintosh designed for the Glasgow School of Art (1907-09) was also an influence. This is apparent in the tall oriel windows, the abstraction of detail, and the mediation between the small scale of the residential buildings and the buttressed structure of the Chapel of St. Peter and St. Paul.
On the inside, the principal point of reference was James Gamble Rogers' School House (1937), until Ohrstrom the last building in St. Paul's chain of Gothic-inspired buildings. Ohrstrom Library incorporates the most up-to-date computerized information retrieval technology into traditional reading rooms and more intimately scaled niches that provide a variety of places for quiet individual or group study within easy reach of the bookstacks. The nave-like plan is entered at the crossing that separates the stacks from the specialized reading rooms, the primary one being a two-storey-high vaulted room that opens to a view of Lower School Pond.