Bookshelf immediately makes all content free to read as NLM believes that the best way to ensure the accessibility and viability of digital material over time is through consistent and active use of the archive. However, free access does not mean that there is no copyright protection (see the Bookshelf Copyright Notice).

Bookshelf stores content in eXtensible Markup Language (XML), which represents the structure and meaning of a document in a relatively simple and human-readable form. All Bookshelf content is converted to and stored in the Book Interchange Tag Suite (BITS) XML format.

Bookshelf leverages the existing PubMed Central® (PMC) software architecture to store and make its content accessible to users.

NLM operates the PMC International network, which provides a framework to maintain copies of the Bookshelf corpus in other reliable international archives that share the goals of PMC and Bookshelf and operate on the same principles.