The BHL portal provides free access to thousands of biodiversity literature and archival volumes, comprising over 55 million pages, from the 15th-21st centuries. The BHL operates as a consortium of natural history, botanical, research, and national libraries that work together to digitize the natural history literature held in their collections and making it freely available for open access.
The core of the BHL collection is focused on the subject matter relevant to the work of zoologists, botanists, evolutionary biologists, taxonomists, systematists, ecologists, natural history collections managers, scientific illustrators, biological science historiographers, and amateur scientists & hobbyists. In selecting materials for digitization, the consortium tries to maximize scanning dollars by prioritizing the core literature from partner's collections, especially those titles that have a high concentration of taxonomic names.
The types of materials in the BHL collection include: Books and Journals, Article Metadata (not Articles), Archival Materials, Book-like objects, and links to materials on third-party websites.
The consortium works with the international taxonomic community, publishers, bioinformaticians, and information technology professionals to develop tools and services to facilitate greater access, interoperability, and reuse of content and data. BHL provides a range of services, data exports, and APIs to allow users to download content, harvest source data files, and reuse materials for research purposes. Through the Global Names Recognition and Discovery (GNRD) service, BHL indexes the taxonomic names throughout the collection, allowing researchers to locate publications about specific taxa.