Technical reports detail the progress or results of scientific, technical, or policy research. Typically, technical reports are produced in response to a relatively narrow research need, and serve as a report of accountability to the sponsoring organization. They generally are not peer reviewed, but often document detailed methodology and data information in order to facilitate review of research by others. Technical reports play a unique role in scientific communication, in that they sometimes are the only source of information on a specific topic, and often report on unsuccessful research results. Technical reports generally are not commercially published, but are issued using techniques that permit rapid, inexpensive, and limited distribution methods. Long-range archiving of these materials generally is accomplished through microformat, and, increasingly, electronic publishing.

Although it is not feasible for the Library to maintain a comprehensive collection of technical reports, the collection does include a great volume of technical report literature. NLM is particularly interested in acquiring technical reports that provide information in emerging fields. Collecting emphasis is on reports published by U.S. federal agencies and eminent international research organizations. NLM also collects less widely disseminated technical reports (e.g., from developing countries) when such reports document scientific activity of international interest, or describe findings unique to the country or culture of origin.

The Library of Congress maintains an extensive collection of technical reports in the sciences and engineering, but generally excludes clinical medicine.