The Darwin Digital Library of Evolution is based at the American Museum of Natural History Library with contributions from the Natural History Museum (London) and the Missouri Botanical Garden. It is a "a pilot project drawing on resources of members of the Biodiversity Heritage Library Consortium". 98 of the approximately 3,500 references listed in the bibliographies are available in full text. Resources range from seventeenth century works and cover the nineteenth century debates as well as modern evolutionary biology. They are organized in four chronological sections: Ancestors; Darwin; Decendents; and Responses and include works in Darwin's personal library.