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. 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. 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.