The Morgan Library, a complex of buildings in the heart of New York City, began as the private library of financier Pierpont Morgan, one of America's greatest collectors and cultural benefactors. As early as 1890 Morgan had begun to assemble a collection of illuminated, literary, and historical manuscripts; early printed books; and old master drawings and prints.

Mr. Morgan's library, as it was known in his lifetime, was built between 1902 and 1906 adjacent to his New York residence at Madison Avenue and 36th Street. Designed by Charles McKim of the architectural firm McKim, Mead & White, the Library was intended as something more than a repository of rare materials. Majestic in appearance yet intimate in scale, the structure was to reflect the nature and stature of its holdings. The result was an Italian Renaissance–style palazzo with three magnificent rooms epitomizing America's Age of Elegance. Called "one of the seven wonders of the Edwardian World" and completed three years before McKim's death, it is considered by many to be his masterpiece. In 1924, eleven years after Pierpont Morgan's death, his son, J. P. Morgan, Jr. (1867–1943), known as Jack, realized that the Library had become too important to remain in private hands. In creating an institution dedicated to serving scholars and the public alike, and in what constituted one of the most momentous cultural gifts in U.S. history, he fulfilled his father's dream of making the library and its treasures available to the public.

Over the years—through purchases and generous gifts—the Library's holdings of rare materials have continued to grow, and important music manuscripts, early children's books, Americana, and materials from the twentieth century have been acquired. Without losing its decidedly domestic feeling, the Library has also considerably expanded its physical space. The Annex was built on the site of Pierpont Morgan's brownstone. Completed in 1928, the addition consisted of a large entrance foyer, a reading room for scholars, and an exhibition hall. The new structure was joined to the original library by means of a connecting gallery called the Cloister (recently renamed the Dr. Rudolf J. and Lore Heinemann Gallery). A dramatic addition occurred in 1987 when the Library doubled its size with the acquisition of Jack Morgan's nearby town house. A garden court was built to connect the house with the Annex and original library. This expansion, completed in 1991, made way for both more exhibitions and a wider array of lectures, concerts, and other educational programs.

Recently the largest expansion in the Morgan's history, added 75,000 square feet to the campus. Completed in April 2006 and designed by Pritzker Prize–winning architect Renzo Piano, the project increased exhibition space by more than fifty percent and added important visitor amenities, including a 280-seat performance hall, a welcoming entrance on Madison Avenue, a new café and a new restaurant, a shop, a new reading room, and collections storage. Piano's design integrates the Morgan's three historical buildings with three new modestly scaled steel-and-glass pavilions. A soaring central court connects the buildings and serves as a gathering place for visitors in the spirit of an Italian piazza.

Fulfilling the vision of its founders, the Morgan Library has become and continues to be an internationally recognized center for research as well as a vital museum serving a diverse public.