Images from some of the items described below illustrate but a few of the New York Public Library's major holdings in science and medicine included in the exhibition Seeing Is Believing,on view from October 23, 1999—February 19, 2000 at the Humanities and Social Sciences Library, and related publication.

At its founding in 1895, The New York Public Library already possessed a splendid array of important books in the fields of science and medicine. These came to the new library from the two private collections whose merger, along with a bequest from the Tilden Trust, created the new institution. The first of those private collections, the Astor Library, founded in 1848 through the bequest of John Jacob Astor, was very strong in first and early editions of astronomy, mathematics, physics, chemistry, medicine, natural history, and microscopy. The Astor Library included such great medical works as the extremely rare first edition of William Harvey's landmark treatise on the circulation of the blood (1628) and William Hunter's work on the gravid uterus (1774). In the sciences, it included the first edition with the rare errata sheet of Nicolaus Copernicus's De revolutionibus orbium coelestium (1543); Robert Hooke's Micrographia(1665); and Leopold Trouvelot's magnificent Astronomical Drawings(1882).

The Lenox Library, founded in 1876 through the bequest of James Lenox, included many important books of science and medicine, as well as many books on natural history from the collection of Robert Leighton Stuart, which had become part of the Lenox Library in 1892. The Lenox Library owned not only the original elephant folio edition of Audubon's Birds of America (1827—38) but also a full set of the never-completed American reprint, made by Julius Bien using the process of chromolithography (1860—61); the Stuart Collection included a copy of Edward Lear's magnificent Illustrations of the Family of Psittacidae, or Parrots (1832), the first illustrated work of ornithology devoted to a single family of birds.

Dr. John Shaw Billings, the first Director of The New York Public Library, was also a physician of considerable stature: he had been Assistant Surgeon General of the United States and head of the Johns Hopkins Medical School prior to his appointment at the Library. He was also a friend and colleague of Sir William Osler, the noted physician and bookman who generously bestowed first editions of Andreas Vesalius's De humani corporis fabrica (1543) on various libraries, including the Library of Congress and The New York Academy of Medicine. (It is conjectured that Osler did not donate a copy to The New York Public Library because he knew that the Academy's copy would be available to the general public.) The first Vesalius Fabrica to come to The New York Public Library was thus a second folio edition (1555), which came as part of the original bequest that formed the Henry W. and Albert A. Berg Collection of English and American Literature. The Berg brothers, whose principal collecting interest was nineteenth-century British and American literature, were both prominent New York physicians, and no self-respecting physician—book collector would have been without a Vesalius. The Bergs were wide-ranging in their definition of literature; they collected, for instance, the works of Charles Darwin, including On the Origin of Species (1859) and The Descent of Man (1871).

The second important Fabrica to come to the Library was purchased in the 1930s. The Library's interest in printing history and the private press movement made mandatory the purchase for the collections of the 1935 Bremer Presse edition, made from the original woodblocks (which would not survive World War II) and published by the University of Munich in collaboration with The New York Academy of Medicine, an institution with which The New York Public Library has always had a special relationship. Because the Academy maintains a medical research library that is open to the public — the only medical library in New York City that affords such access — The New York Public Library does not seek to duplicate its resources, and therefore collects medicine only in cases where a medical book complies in some other way with one of the Library's collecting policies, such as printing history, the African American experience, and medicine in art and music.

After the death of John Shaw Billings in 1913, Anna Palmer Draper, a major supporter of the Library in its early years, made provisions for a special fund in his memory: when she died the following year, her bequest to The New York Public Library included not only her own books but also the sum of $200,000 to endow "The John Shaw Billings Memorial Fund." Proceeds from this fund have been used to purchase special works that the Library could not otherwise afford to acquire, including first editions of Euclid's Elements (1482) and Newton's Principia (1687); the first edition of Thomas Geminus's reprinting, using copperplate engraving, of Vesalius's Fabrica (1545); and the second edition, but first French translation, of Charles Estienne's La dissection des parties du corps humain (1546).

The Spencer Collection of illustrated books in fine bindings came to the Library in 1913 after the death of William Augustus Spencer on the Titanic, on April 14, 1912. The original collection has grown considerably, thanks to a fund that came with the books and carried the directive to purchase "the finest illustrated books in fine bindings that can be procured of any country and in any language, and to be bound in handsome bindings, representing the work of the most noted bookbinders of all countries, thus constituting a collection representative of the arts of illustration and bookbinding." Among the Spencer Collection books in Seeing Is Believing are the first editions of Joannes de Ketham's Fasciculo di medicina (1493), Otto Brunfels's Herbarum vivae eicones (1530), and Leonhart Fuchs's De historia stirpium (1542); and one of the dozen known copies of Anna Atkins's British Algae (1843—53), the work of the first woman photographer.

Over the course of the past century, the Library's scientific collections have continued to grow. In 1934, the Library's science and technology collections were augmented by the acquisition of the library of William Barclay Parsons, the engineer for the New York City subway system. The gift of Mrs. Parsons, the collection is devoted to engineering and transportation, and includes a great many rare books, including the first printed edition of the works of Archimedes (1544), and is now housed at The New York Public Library's Science, Business and Industry Library.

Most recently and notably, the Library received in 1995 the gift of the Wheeler Collection of Electricity and Magnetism. This gift from the United Engineering Trustees consisted of the library formed by Josiah Latimer Clark, which represented one of the most complete collections of books and periodicals on the subject of electricity assembled in the nineteenth century. It was Clark's wish that his library should eventually go to the United States, since the library of his colleague, friend, and rival collector Sir Francis Ronalds was to stay in London. The move of the collection was accomplished through the good offices of Schuyler Skaats Wheeler, who purchased the Latimer Clark Library in 1901 and presented it to the American Institute of Electrical Engineers in New York City. In 1903, Andrew Carnegie contributed funds to house, catalog, and add to the Latimer Clark Library, which became known as the Wheeler Gift.

As one of the stipulations of his gift, Mr. Wheeler required that the "Library remain in New York City and . . . be a reference library, free to all." In 1995, when the overseers of the collection, the United Engineering Trustees, decided to give up running a library, the Wheeler Gift came to The New York Public Library, where it is administered by the Rare Books Division. Important Wheeler books in Seeing Is Believing include William Gilbert's monumental De magnete (1600), the first major English scientific treatise based on the then-new experimental methods of research; Luigi Galvani's De viribus electricitatis in motu musculari (1791); and James Clerk Maxwell's Treatise on Electricity and Magnetism (1873).