In the world of books and libraries, an index is an organized listing of where information can be found within a book, within a collection of books, within a periodical, or within a collection of periodicals. Without indexes, research would be a cumbersome process at best.

The most commonly thought of form for an index is the alphabetically arranged listing of topics and names found at the end of a book. A book's index allows a reader to skip around to specific content within the book without following the content linearly. But indexes also are useful in providing researchers with access to periodical contents, to contents of books of essays, and even to the contents of collections of books. In most cases, an index is arranged alphabetically by topics, by key concepts, or by names, but indexes can also be arranged chronologically, by classification system, or by some other specialized scheme. Indexes may also provide location information by author's name or by title.

A library's catalog is an index of materials contained in the library's collections. Arranged by subject heading, by author, and by title, the catalog helps users to identify relevant materials in a library's collections and to locate them physically within the library's collections. Without an index to the library's collections, a user would have to resort to browsing the shelves to locate needed information. This might work alright in an individual's own personal library, but in a public or university library collection which contains thousands of titles, this would be grossly inefficient and time consuming. Serendipity would figure heavily into a person actually finding exactly what was needed using the browsing approach. For this reason, books have indexes, libraries have catalogs, and periodicals have reader's guides.

Access to a book's content is traditionally provided in two ways: via a table of contents and/or via an index. Although a table of contents provides a useful general view of how material in a book is organized, it does not provide an efficient means for locating individual bits of information within a book. An index, which is usually provided at the back of a book, provides a reader quick access to the specifics provided in a book. A book on doing library research, for example, might list periodical indexes as a topic covered in its table of contents, but, if a reader was interested only in finding out about a particular periodical index, say for example the Humanities Index, he or she would be obliged to scan the entire chapter on indexes in order to find it. An index at the end of the book, however, would likely have an entry for the Humanities Index that would take the reader directly to the appropriate page or pages within the book. For quick access to specific information within a book, an index is indispensible.

Library catalogs and book indexes are not the only types of indexes. Other indexes include indexes to periodicals, indexes to newspapers, and indexes to collected works or anthologies. Each of these three types of indexes provides location information for shorter works that have been published within larger publications, such as news articles, feature articles, research articles, short stories, etc. Library catalogs do not provide subject access to these types of materials; they will identify for a library user that the library subscribes to the New York Times or to National Geographic or to Best American Short Stories of 1998, but they will not provide access to the content of these regularly published titles. For this, a researcher must consult a specialized index that keeps track of smaller works published within newspapers, periodicals, or anthologies.

Periodical indexes are some of the most frequently used and valuable indexes published. Since being able to find the most recent literature available on a research topic is of extreme importance to most researchers, periodical indexes are an indispensible part of the research process. These carefully organized publications/databases analyze the content of hundreds and even thousands of regularly published titles (periodicals) and provide researchers with numerous means for accessing the content of these publications. To find out, for example, if anyone had published a recent article on the safety of influenza vaccines in the New England Journal of Medicine, a researcher has two options, one slow and cumbersome, the other quick and efficient. If this periodical were not indexed in a periodical index, a researcher would have to resort to manually browsing the journal's table of contents issue by issue over a period of time. This is slow, inefficient, and cumbersome. Since the New England Journal of Medicine is indexed in several different periodical indexes, along with other important medical journals, the best approach is for the researcher to choose an appropriate periodical index and to scan the index by topic for the time period he or she wants to cover. This approach will also uncover related articles in other medical journals, providing the researcher with a better picture of what research is currently being done or has recently been reported.

In addition to providing researchers with access to articles by topic, many periodical indexes provide several other index arrangements within the same volume. For example, the Current Index to Journals in Education (CIJE) arranges materials published in hundreds of education periodicals by main entry (major subject classification and accession number), by descriptor, by author, and by journal contents. It also provides in each issue an index to the source journals covered in the CIJE. The process of providing multiple accesses to information within periodicals in a single indexing system has been greatly enhanced by the use of computers. The underlying work of analyzing articles and categorizing them by topic, by author, by other identifying characteristic, is still a labor- and brain-intensive process performed by trained professionals. Behind nearly every periodical index is a staff of hundreds of individuals whose responsibility is to provide accurate access to information by classifying and, in many cases, summarizing the content of thousands of periodical articles. (See Note 1 below)

Any search for information, to be thorough, should cover not only books but periodicals. This is especially important for research on any current or new topic, since emerging information is too new to appear in books. Primary reasons for using periodicals are: 

• The most recent material on a subject, especially in the fields of science, technology, statistics, politics, and economics, will be found in periodicals.
• Subjects too new, or even too obscure or too temporary, to be covered by books are treated in periodicals.
• The trend of interest or opinion at any given period is traced easily in periodical literature. The current issues give contemporary information, and the old issues give a record of past ideas, problems, and accomplishments.
• Books, or parts of books, often appear in periodicals before they are published as separate volumes.
• Professional literature is supplemented by periodicals, which keep teachers, scientists, physicians, economists, lawyers, and members of other professions up to date. 

A periodical index is a necessity to a researcher looking for information in magazines and journals. Although some periodicals provide their own subject indexing, these specialized indexes are not common and are usually published only once yearly, or sometimes only once every five years. The only sure way to search periodicals by subject in a timely manner is to use a regularly published periodical index like the Readers' Guide to Periodical Literature. 

Once a researcher successfully locates an article or articles by topic within a periodical index, the index provides location information for the article. Information typically provided to help a researcher pinpoint an article within a magazine or journal include

author's name,

article title,

periodical title,

periodical volume, issue number, and date, and

pages on which the article appeared.

This information is typically not enough, however, to get a researcher to the material in a library's collections unless the library arranges all its periodicals on the shelves by title and by date. This isn't the case in most larger libraries. Periodicals are usually arranged on the shelves by call numbers, which means a researcher will still need to use the library's own index, or catalog, to find out where a particular periodical is located.

No two periodical indexes are exactly alike. Although they all have as their goal facilitating locating articles in many periodicals, the types of periodicals they cover and the scope of coverage varies from one index to another. The researcher's choice of the best periodical index for his or her research is an important element in successfully researching current periodical literature.

Generally speaking, periodical indexes are of two major types: generalized and specialized. The most widely know general index to periodicals is the Readers' Guide to Periodical Literature. This index is considered a generalized indexed because it covers a variety of periodical publications and will cover almost any subject interest. A researcher can expect to find articles of current interest covered in such publications as Time, Newsweek, Scientific American, Rolling Stone, etc., but will find that detailed coverage of a topic in applied research publications is better facilitated in a specialized periodical index. Specialized periodical indexes such as Psychological Abstracts, or ABI/Inform, or Sociological Abstracts will provide researchers with more appropriate articles than will the Readers' Guide. Finding the right index to use can be a challenge, but a researcher can either ask a Reference Librarian for guidance or search the library's catalog for indexes for a certain subject. In either case, a library user must first identify the major subject area to be searched and then know how to search the library's catalog for indexes for that subject. 

In the UNF Library, a researcher can search the library's catalog for periodical indexes by keyword. For example, a search of the catalog for the keywords humanities and index? (the question mark following the root word will produce singular, plural, and other variations of the word) will result in a list of indexes that includes the Humanities Index, a standard periodical index useful in searching for articles on music, art, literature, etc. Other library resources that include the two words will also be retrieved in such a search. Some may be useful, others may not. The researcher will still have to find the resources and examine them to determine if they are potentially useful. When choosing an appropriate index, additional criteria to consider are the time periods covered by the index and whether it is a print or computerized index. Although most subjects are now covered by computerized indexes, not all libraries have all computerized indexes, so it is important to be able to find print indexes also. For example, the UNF Library does have a good general index on computer that covers most of the publications included in the Readers' Guide, but criminal justice periodicals are only sparsely represented in this index. A better index to use for this subject is the Criminal Justice Periodical Index (CJPI), which is the major index to literature on criminal justice. 

In many cases, one periodical index will not cover fully the information necessary to complete a literature search. The topic teen pregnancy, for example, would need to be searched in several periodical indexes to ensure adequate coverage. Expanded Academic ASAP will cover many aspects of the topic, but not all. Other indexes that would yield appropriate information include PsycInfo, Sociological Abstracts, and ERIC. The main things to keep in mind when selecting an index to periodicals are its recency and the scope of its coverage. If one index covers only a couple of hundred sources, a complete search of available material is not possible using that one index. ALWAYS look for other related periodical indexes to perform a complete search of a subject. 

Although periodical indexes are usually thought of as means for finding the most recent literature available on a topic, periodical indexes can also help researchers identify valuable source of historical information. If, for example, a researcher needed to know what contemporary thought was on abortion in the 1920's, one way to discover this is to consult periodicals published during that time period. Some periodical indexes do provide indexing going back even into the 19th century. To find contemporary thought during a historical time period, a researcher will need to explore periodicals published during that period. Periodical indexes provide the wherewithal to do so.  

Some periodical indexes also provide selective indexing to newspaper articles in major newspapers. The extent to which they cover a newspaper's content varies, but is usually limited to articles of national or international interest. To provide complete access to news items included in their pages, major newspapers like the New York Times, the Times of London, and the Washington Post have their own indexes. A thorough search of a newspaper can be accomplished ONLY by using a newspaper index. To find a newspaper index in the UNF Library, you can search the catalog by the title of the newspaper and by using the keyword index?. For example, to find an index for the New York Times, a researcher would enter into the catalog a title keyword search for New York Times combined with a keyword search for the word index? (the question mark, again, allows for variations of the word index). This will provide the location and call number for the index to the New York Times housed in the UNF Library's Index/Abstract Collection. For coverage of many newspapers, regional, national, and international in scope, a researcher might wish to investigate using NewsBank or the Lexis-Nexis collection of newspapers. These specialized computer services provide full text searching of articles from hundreds of newspapers. UNF Library provides its users with access to both systems.

Besides newspaper and periodical indexes, researchers can find recent articles or essays that have been published in books by using indexes such as the Biography Index and the Essay and General Literature Index. Works of short fiction and poetry that have appeared in collections can be located using indexes such as the Short Story Index and Granger's Index to Poetry. Both of these are indexes that offer users multiple accesses to works that might otherwise be difficult to locate. To find these indexes in the UNF Library without already knowing their exact titles, use the same techniques mentioned above. If you're really stumped, remember that libraries provide assistance and training to their users through their reference staff. Ask a reference librarian for further assistance.

---

Note 1. Although by and large most periodicals are still analyzed by people, some indexing systems have automated the indexing process to a large extent. A notable example is the Social Sciences Citation Index. This specialized periodical index analyzes articles by title words, by authors, and by cited references and is largely computer generated. Although the index provides subject access to articles, the subject index is based solely on title words and not on any human analysis of article contents. Much research continues to be devoted to using computers to analyze article content, but no one system has yet proven to be so reliable as to obviate the need for human indexers at this point in time.