After graduating from the University of Pennsylvania in 1974, I served a classic apprenticeship, working for four leading antiquarian booksellers in San Francisco, New York, Philadelphia, and Los Angeles. In 1978 I started my own company - Jonathan A. Hill, Bookseller, Inc. - and have specialized in science, medicine, natural history, bibliography and the history of book collecting, and early printed books. Over the years I have issued 200 catalogues devoted to these subjects. My wife, Megumi Kaneko Hill, and I work together in the business. Some of our clients include The Library of Congress, Harvard University, The British Library, the Bibliothèque Nationale (Paris), the Staatsbibliothek zu Berlin, the National Diet Library (Japan), and many leading and well-known private collectors. Many famous books have passed through our hands, including first editions of Aristotle, Copernicus, Vesalius, Harvey, Newton, Darwin, and Einstein. We also specialize in important manuscripts related to the history of science, technology, and medicine as well as illuminated manuscripts. We work closely with private collectors, museums, and libraries, selling them books from our stock, advising them on other acquisitions, performing appraisals, and representing them at auctions in America and throughout Europe. We issue four to six printed catalogues a year and update our web-page with recent acquisitions on a weekly basis. We are members of the Antiquarian Booksellers Association of America, the International League of Antiquarian Booksellers, and the Verband Deutscher Antiquare and are pleased to adhere to their codes of ethics and practice.