Abraham Simon Wolf Rosenbach ( July 22, 1876 — July 1, 1952) was an avid American collector, scholar, and seller of rare books and manuscripts.
Abraham was the youngest of the eight children of Morris Rosenbach (May 14, 1820 — May 8, 1885) and Isabella H. Polock (November 26, 1834 — July 25, 1906), who were married on November 11, 1857. As a child, Abraham spent much time in the shop of his maternal uncle, Moses Polock (May 14, 1817 — August 16, 1903), a well-known and somewhat eccentric antiquarian bookseller. Polock's famous shop was located at 406 Commerce Street in Philadelphia. Abraham got his start collecting while a freshman in college at the University of Pennsylvania. His company, simply called the Rosenbach Company, went on to help assemble the extensive collections of the Huntington Library and the Folger Shakespeare Library. He also worked for private clients such as J. P. Morgan, Lessing Rosenwald, and Harry Elkins Widener. He published several articles and even books in order to reinforce the interest in rare books and manuscripts.
Rosenbach is credited with popularizing the collecting of American literature at a time when only European literature was considered collectable. He also advanced the idea of book collecting as a means of investment.
Dr. A.S.W. Rosenbach died, aged 75, in Philadelphia. His legacy is the Rosenbach Museum & Library. A lifelong Philadelphian, Rosenbach lived on Delancey Place, the small, residential street where the museum is located, from 1926 to 1952. He was a collector and scholar who parlayed his passion for books and manuscripts into a successful business, becoming the most famous dealer in rare books and manuscripts in the first half of the 20th century, who helped to build some of this country's most important private collections, always urging their transformation into public libraries.