What the Heck is a Book Index?

Katie Moench


Katie Moench is a librarian, runner, and lover of baked goods. A school librarian in the Upper Midwest, Katie lives with her husband and dog and spends her free time drinking coffee, trying new recipes, and adding to her TBR.

There are many parts of books, from the folio page to the end credits, that the casual reader might fly right by without noticing the detail that goes into each element. Rioter Kelly Jensen recently wrote a great article on credit pages in books, a rarely seen example of paratext that would acknowledge the myriad people that have an impact on a book’s non-narrative aspects. When it comes to nonfiction, especially encyclopedic works, a key paratext element is an index. Indices (yes, that’s the plural of index) are alphabetical listings of the major topics and subtopics in the book, with page numbers for where those readers can find them referenced. But how do these indices actually come to be? And are there best practices in creating them? Let’s take a look!

What kinds of books get an index?

Generally, indices have been included at the back of any nonfiction books that broadly fall under the research category, meaning that they’re less likely to appear in nonfiction books that fall into categories like memoir or narrative nonfiction. While there’s no hard and fast rule as to which books get indices, a general rule is to think about how the average reader will be using the book, and then it’s up to the author and publishing company whether one is included. If the book is any kind of textbook or other reference text, it will be pretty much guaranteed to have an index, but indices also show up in works like cookbooks or coffee table books, which are more often used for recreational reading. The purpose of the index is to give the reader an easy way to reference specific chunks of text or information and can also be a useful way to quickly find images or tables included in the book. In fact, some books may have an entirely separate index for images, maps, or other aspects of the text in order to make this experience easier. 

What does an indexer do? Who are indexers and how do I become one?

Indexers come to the job from all kinds of backgrounds, many indexers are freelancers or may work for a publisher/in the world of books in another capacity. Though indexing may seem like a simple and straightforward role, it requires an incredibly patient and detailed approach to ensure that readers can easily access the information they’re looking for. Just think, for example, about someone working to index a reference work of historical nonfiction. Would an index make its major headings people? Time periods? Wars? Geographic locations? How big of a mention does something need in the text before it gets its own index entry? All of these are questions indexers must grapple with when completing a job. 

An indexer starts, perhaps obviously, by reading the book in question. Many indexers may read a book multiple times, in order to get a sense of the main topics and how they connect throughout the work. Then, the indexer will begin to mark up the text to determine the main headings, subtopics, section headings, and key terms that will make up the index. Some indexers these days use indexing software to help them cluster entries around headings and subheadings, while others use the old school method of marking up a hard text and sorting entries using index cards. Either way, it is up to the indexer to develop a method of organization that will bring order and utility to the text. 

Once the text has gone through an initial markup, it’s time to address issues of formatting and style. First, the indexer will need to decide how topics will be cross-listed and if there will be special indications of images or other text features, and how main headings and subheadings within the index will be differentiated. Then, it’s time to list the entries alphabetically, do a copy edit of the entire index (which will include double-checking page numbers for accuracy), and get feedback from the author and publisher. Once each of these tasks is completed, the index is ready to become a part of the published volume.

So, if the responsibilities above appeal to you, how does one become an indexer? As previously mentioned, many indexers work as freelancers who rely on past clients and word of mouth in order to find new projects. Indexers with a specific knowledge base may be in demand for certain projects; for example, a scientific textbook company may want to keep indexers on hand that understand how to categorize information within that subject. Interested indexers can take classes through organizations like the American Society for Indexing, or pick up books that walk them through some of the basics, but there is no official certification required for the role. Generally, indexers are detail-oriented and have a sincere interest in organizing information, as well as the ability to pick up on themes in a text. In addition to books, indexers may work with materials such as genealogical information or legal filings, or they may work as a website or database indexer, organizing information virtually. 

Overall, indices may be one of the most crucial, yet overlooked, pieces of paratext a book can contain. Just think of how much more unwieldy a textbook would be without a solid index, or how much less useful a cookbook would seem if you didn’t have recipes indexed by their main ingredient. Indexers take vast amounts of information and give readers a way to access it in a matter that is more efficient and useful than it would otherwise be. A good, solid index elevates the ability of an author to share knowledge, which is why it’s such a crucial job within the publishing world.