You may be familiar with one kind of index -- the alphabetical listing of topics in the back of a book -- that helps you find where a particular topic is covered in the book.
There is another kind of index that helps locate articles in periodicals - newspapers, magazines, and scholarly journals. In the twentieth century, subject indexes to the content of journals and newspapers - usually in a particular field of information - were published in book form and provided the best way to find articles on a particular topic. After all, even before computers people wanted to be able to find what information was published about a certain topic. For example, Art Index contained article citations from hundreds of journals and magazines in the field of art and included listings (indexes) by author, title and subject for each citation. You could look up a topic or artist, like Mona Lisa or Picasso, alphabetically in the subject listing and find out what articles had been published about it that year in art sources.
Most of these print indexes have been replaced by computer databases that do exactly the same thing -- contain thousands of citations to resources such as books, articles, etc. that can be searched by keyword, author, title and subject. Many may still include the word "index" in the title.
