Subject encyclopedias concentrate on topics within a specific discipline (e.g., education, philosophy, art, or technology).
Like general encyclopedias, they provide more comprehensive information than dictionaries. In addition to definitions, they may include descriptions, historical background, statistics, and other details about the topic. Extensive bibliographies, listing other materials on the topic, are often provided.
McGraw-Hill Encyclopedia of Science and Technology is an example of a subject encyclopedia that has background information on space station technology.