National bibliographies attempt to describe the publishing output of a specific region of the world. Most national bibliographies will also be circumscribed by a time period. Examples of national bibliographies include:
National bibliographies will usually include an introductory essay on the printing history of the nation or region covered. They will be organized either alphabetically by author, chronologically by date of publication, thematically by broad subject, or some combination of the above. A really good national bibliography will include at least some indexes, such as a general subject index, an author index, and maybe an index of printers and publishers. However, national bibliographies vary widely in scope, detail, and quality.
National bibliographies are useful to the historian in helping him or her establish the publishing output of a nation or region: in the search for primary sources, they help to answer the question, "what documents were actually published in a given place at a given time?" Without this knowledge, a historian could waste hours, days, weeks, and even months searching for publications that were never produced in the first place.
Not all national bibliographies cover the publishing output of an entire nation. Some national bibliographies will cover an entire continent, while others will cover a region within a nation. For example:
To learn much more about national bibliographies, see the guide created by the Slavic Reference Service on National Bibliography.