Locations vary, ca. late 18th to early 20th centuries. Comprising approximately 150 items, including pamphlets, books, and other material by and related to the life and work of James Sowerby and various family members, including an original watercolor of a blue whale and four volumes bound in half-vellum of various articles by and about Sowerby, as well as notes and books owned by or about James de Carle Sowerby, William Sowerby, Arthur de Carle Sowerby, and others.

The Sowerby family is considered to be one of the most significant in the field of natural history, having produced several generations of naturalists, botanists, and zoologists, beginning with James Sowerby (1757-1822), whose 36-volume magnum opus, English Botany, was printed over twenty-three years. His son, James de Carle Sowerby, was a co-founder of the Royal Botanic Society and Gardens, and his great-great-grandson, Arthur de Carle Sowerby, was a naturalist and cartographer whose work in China and its surrounding regions contributed greatly to early 20th-century Western understanding of the environment and natural history of the area.