William Swan Sonnenschein was born in 1855, third of the six children of Adolphus Sonnenschein, a teacher and writer of textbooks originally from Moravia, and his first wife Sarah Robinson Stallybrass. William's name derived from the fact that his maternal grandfather, Edward Stallybrass, had been a missionary to Mongolia with William Swan and they worked on a Mongolian translation of the New Testament together.
As a young man William was apprenticed to the firm of Williams and Norgate where he gained experience of second hand bookselling before founding his own company, W. Swan Sonnenschein & Allen, with the first of several partners, J. Archibald Allen, in 1878. This partnership was dissolved in 1882 when William married and the firm's name changed to W Swan Sonnenschein & Co. The firm published general literature and periodicals but specialised in sociology and politics. Sonnenschein was involved with the Ethical Society and published their literature.
In 1895 Swan Sonnenschein became a limited liability company and in 1902 William Swan Sonnenschein left to work at George Routledge and Sons and later at Kegan Paul. Swan Sonnenschein was amalgamated with George Allen & Co in 1911.
In the light of the hostility to Germans during the First World War William Swan Sonnenschein changed his surname to Stallybrass for the remainder of his life as did some, but not all, of his family. He died in 1934.
From the guide to the Archives of Swan Sonnenschein & Co, 1878-1916, (Reading University: Special Collections Services)