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Library of Congress Science Tracer Bullet Inventory (1972-2013)

Compiled by science reference specialists, Library of Congress Tracer Bullets were bibliographic guides published between 1972 and 2013. This guide provides an index to all Tracer Bullets and provides links to digital copies when available.


Sheri Weisberg, artist. Keeping Up With Science. Between 1936-1939. Library of Congress Prints & Photographs Division

This guide provides an inventory of the Library of Congress Tracer Bullet series. In addition to their titles, Tracer Bullets were identified by a number indicating the year of publication, followed by the issue number; this inventory allows access to the titles by either title or by year and issue number. Links are provided when available to the Tracer Bullets that are accessible online, but some titles may be available only in print format.

What is a Science Tracer Bullet?

The Library of Congress Science Tracer Bullet series (ISSN 0090-5232) was an informal and irregular series of library pathfinders published from 1972-2013. They were designed to help someone begin to locate research materials on a subject about which they held only general knowledge.

These guides were produced by expert reference staff of the Science & Technology Division's Science Reference Section, and, on occasion, by guest librarians, consultants, interns, and volunteers. Most guides were aimed at the undergraduate level, however some, particularly those involving science fair projects, were written with parents and educators in mind. The Tracer Bullets were distributed as government documents to government depository libraries. In 1990 Omnigraphics, Inc. republished 173 of the titles in four volumes.

For more information on library pathfinders see "Library Pathfinders: a New Possibility for Cooperative Reference Service External," by Charles H. Stevens, Marie P. Canfield, and Jeffrey J. Gardner, in College and Research Libraries News, v. 34, No 1 (1973).

What features are included in a Science Tracer Bullet?

One of the important aspects of the Science Tracer Bullet is that the progress of the information in the format of the bibliographic guide is supposed to mimic the research process itself. The prescribed format defines a scope, gives review articles and basic texts, and then leads the researcher on to suggestions for finding additional information.

The major features of a Science Tracer Bullet include:

  • a weighted list of subject headings, which can be used in searching a library card catalog
  • a list of basic texts
  • lists of bibliographies, state-of-the-art reports, conference proceedings, or technical reports
  • a list of journals in which one can usually find articles on a particular subject
  • a list of abstracting and indexing services, or databases, useful in finding journal articles and government publications
  • the names and addresses of organizations to contact for additional information
  • a list of selected internet sources

Why are they called "Tracer Bullets"?

"Tracer bullets," also called "tracer rounds," are usually loaded as every fifth round in machine gun belts. They provide essential information to soldiers firing at an enemy target by creating a line-of-sight that allows them to track the trajectory of their bullets and adjust their aim. Because these compilations were intended to put a reader "on target," they were called "tracer bullets."

About the Science Section

Part of the Science & Business Reading Room at the Library of Congress, the Science Section is the starting point for conducting research at the Library of Congress in the subject areas of science, medicine and engineering. Here, reference specialists in specific subject areas of science and engineering  assist patrons in formulating search strategies and gaining access to the information and materials contained in the Library's rich collections of science, medicine, and engineering materials.