The following is an overview of the types of literature you will find in the sciences (librarians use the term “literature” to cover any sort of published or distributed information, and so it covers articles, books, websites, video, images, and so forth). There is a large and always-growing amount of information published in academic fields, and it is helpful to have an idea of what kind of information source you’re after.
There are three basic “levels” of literature:
Primary Literature: accounts of original research, written by the researchers who performed it. Primary literature must provide enough information to allow another researcher (with the right skills) to reproduce the experiment. Examples: journal articles, conference proceedings, dissertations, and patents.
Secondary Literature: This type of literature refers to the primary sources, in some cases synthesizing information from primary sources to draw new conclusions, or repackaging it in a new form. Generally, secondary literature does provide new or additional information or criticism on the topics discussed. Examples: monographs (a fancy word for books), encyclopedias, some textbooks, and annual reviews.
Tertiary Literature: Tertiary literature is primarily used as a finding aid for primary and secondary literature, and does not usually provide any new information. Examples: directories, indexes, and bibliographies
In terms of importance for scholarly research, primary literature is the most important type is primary literature. Secondary and tertiary literature are there to assist you in locating and understanding the primary literature, but it is the first-hand accounts of actual research that let you know what has been done, and what researchers have discovered.
This section is aimed at helping you understand, for example, what the difference between an encyclopedia and a handbook is.
Abstracts & Indexes: abstracting and indexing services are the primary means for a researcher to stay abreast of developments in his or her field, and to locate research that is relevant to his or her own area of inquiry. These services collect and publish citations and abstracts to scholarly articles from journals around the world, which researchers can use to locate the full text of the relevant article. Abstracts are collected chronologically (for example, a single volume of one of these services would contain all of the articles published during a 6-month period). These services originated in print, but most can now be found in electronic formats.
Bibliography (or Literature Guide): this kind of work is usually the product of extensive research into the scientific literature, aimed at providing the reader with the citations for a broad list of information sources of all types (books, journals, dictionaries, web sites, etc.) that can be found in the field.
Conference Proceeding: these consist of the papers that are presented at a professional conference, collected into a single volume. Conferences are one of the first areas that research findings are often discussed, and many of these papers will go on to be formally published in the scientific literature. Research results discussed in conferences may be preliminary.
Database (also sometimes called a Bibliographic Database): these sources represent a great leap forward in convenience for accessing scientific information, from citations and abstracts for articles across the sciences, to in some cases the full text of an article. Databases are electronic sources, but take care not to confuse them with sources from the “open Internet” or the “open Web.” While databases use Internet technology to transmit the information they contain, they are carefully maintained and designed, and the information they carry is evaluated by the database vendor to ensure accuracy and credibility.
Dictionary: works of this type provide short-to-moderate length definitions of terminology in a particular field. They are useful when researching, to define unfamiliar terms. The boundary between dictionary and encyclopedia blurs in the sciences at times; it is not unusual to see titles such as The Encyclopedic Dictionary of (Subject).
Directory: these works usually provide contact information for organizations, individuals, or institutions working in one of the scientific disciplines. For example, the International Research Centers Directory provides contact and other information for non-U.S. research organizations.
Encyclopedia: encyclopedias offer topic-specific entries that are usually aimed at a fairly general audience. Entries can be varied in length–more extensive or longer-lived topics tend to have very long entries, while newer or less important topics can have shorter entries. Some encyclopedias provide signed articles (that is, the author of each entry is indicated); some also provide bibliographic references for further research.
Handbook: handbooks typically collect useful quick-reference information, such as physical constants, handy formulas, chemical data, and diagrams in a single source to be used as a companion to the researcher’s work.
Journals: journals are the most important source for a researcher to consult, as they constitute the “moving front” of scholarly research. As researchers perform experiments, collect data, and evaluate the results, their goal is usually to publish the information in a scholarly journal, where it can be distributed to the larger academic community. To pass muster with the academic community, journal articles undergo peer review, during which they are read by other experts in the field, who will comment on the article’s quality and importance, suggest areas for improvement, or ask additional questions about the research.
Journal articles vary somewhat from discipline to discipline, but typically contain the following elements:
Journal articles should contain sufficient information for another scholar skilled in the discipline to reproduce the experiment.
Website: this is a fairly self-explanatory “literature type,” but has a couple features that bear mentioning. First, the web has been a major boon to the distribution of scholarly information. However, with scientific websites like any site, one must be cautious to verify its accuracy, credibility, and currency before assuming the information is valid. See Finding and Evaluating Information on the World Wide Web for more information.