William Swan Sonnenschein

William Swan Sonnenschein (5 May 1855 – 31 January 1931), known from 1917 as William Swan Stallybrass, was a British publisher, editor and bibliographer. His publishing firm, Swan Sonnenschein, published scholarly works in the fields of philosophy and the social sciences. In 1895 the firm became a limited liability company.

Under him the firm published several renowned book series, including the Library of Philosophy (1890–1911) and the Social Science Series. The firm also acquired a reputation for publishing radical works, including those of George Bernard Shaw, Karl Marx, and Edward Carpenter. Other major authors published were J. M. Barrie, Henry James, George Meredith and George Moore.

He was a member of the Ethical Society and published its literature.

In 1902 he left Swan Sonnenschein to work as senior managing director at the publishing house George Routledge & Sons.

In 1911 the firm Swan Sonnenschein became amalgamated with George Allen & Co.

Sonnenschein wrote The Best Books, a multivolume general bibliography that became a standard reference book in larger libraries for many years. Its third edition (1910) was described by The New York Times as a "valuable work".

Books written The best books : a reader's guide to the choice of the best available books (about 25,000) in every department of science, art, and literature, with the dates of the first and last editions, and the prize, size and publisher's name of each book. A contribution towards classified bibliography. London: Swan Sonnenschein, Lowrey & Co., 1887. The best books : a reader's guide to the choice of the best available books (about 100,000) in every department of science, art, and literature, with the dates of the first and last editions, and the prize, size and publisher's name (both English and American) of each book. A contribution towards systematic bibliography. 3rd ed. London: George Routledge and Sons, 1910–35.