Biodiversity Heritage LibraryThis is an open access resource with access to over 100,000 books and journals.
"The Biodiversity Heritage Library (BHL) is a consortium of natural history and botanical libraries that cooperate to digitize the legacy literature of biodiversity held in their collections and to make that literature available for open access and responsible use as a part of a global “biodiversity commons.” The BHL consortium works with the international taxonomic community, rights holders, and other interested parties to ensure that this biodiversity heritage is made available to a global audience through open access principles. In partnership with the Internet Archive and through local digitization efforts, the BHL has digitized millions of pages of taxonomic literature, representing over 100,000 titles and over 170,000 volumes."