Insights into the world of indexing

Cookbooks, handbooks, textbooks, scholarly monographs, catalogues: a good index is still essential across a range of non-fiction books. Indexes help readers find the information that they need and are often the first point of entry to a text – many of us will have browsed the index before committing to buying a book.

Indexes are made by professional indexers, who anticipate the needs of all sorts of readers when choosing the terms that will form part of an index. That’s why an index always wins out over a simple search – the indexer will have weighed the significance of each mention of a term, only including those in the text where there’s useful information to be found. Back-of-the-book indexes remain standard in print books, and eBook technology allows pinpoint indexing to the exact place in a book where a topic is discussed, with a clickable link to take you there.

Who are indexers?

Indexers come from different working backgrounds: there are former librarians, teachers and academics, lawyers and doctors, as well as publishing professionals. They often have considerable expertise in the subjects that they index and can be highly qualified. Some also specialise in particular types of publications, such as biographies, children’s books or journals.

The Society of Indexers (SI)’s membership base reflects this variety of expertise. It is the only autonomous membership body for indexers in the United Kingdom and Ireland. Many members combine indexing with editing and/or proofreading as part of a portfolio career. Like proofreaders and editors, they’re nearly always freelancers working in the publishing industry.

Indexing can be an interesting, satisfying and intellectually challenging career – with the bonus of reading for a living.

Working with indexers

Working with a professional indexer will enhance the quality, and sales, of a book. Authors and publishing professionals can find a suitable indexer for their project through the SI Professional Directory. It’s helpful to contact your indexer and place the project well in advance of any deadlines, as they do get booked up. Ideally, you would book your indexer once you start to plan the project schedule, and give two months' notice. However, like most freelancers, indexers can often take on a project at short notice. Before you brief your indexer, make sure you have all the information you need about the project and your publisher’s usual requirements for indexes such as layout, style and length. The costs of indexing vary according to the extent and complexity of the book; the SI’s recommended rates are a good starting point for negotiation.

Artificial intelligence (AI) and indexing

Like many professions that work with language, AI is affecting indexing. Automated tools for indexing have existed for some time but have not been able to produce a quality index. They cannot reproduce the human skills of judgement and analysis in context. Generative AI tools work by predicting the most likely next word rather than informed understanding and empathy.

Current AI tools like ChatGPT will, if asked, create an index for a work in the public domain, but the headings inevitably need review and the page numbers are often inventions. AI tools that create summaries of text or extract keywords could be useful during indexing, but an AI tool alone won’t have the human indexer’s insight into readers’ needs. And there are legal issues involved in sharing any book with an AI tool that will incorporate the text into a large language model.

Indexers make good use of technology, however. Indexing software takes a lot of the drudge work out of indexing. Changes to proofs can be dealt with more easily and indexes repurposed for revised editions. Embedded indexing, where the index entries are coded into a Word manuscript, InDesign file or similar, generates an index that is automatically populated with page numbers. This is very useful for texts that will appear in various formats and especially helpful for eBook indexes.

Discover more about indexing

If you are interested in a career in indexing, or honing your skills, the SI website and blog is the best place to start. You’ll find plenty of useful information – including the qualities you need to be an indexer, professional training and workshops, the index commissioning process, the qualities of good and bad indexes, the negotiation of fees, and more.

If you want to learn how indexing works, Indexing for Editors is ideal. This workshop explains the commissioning process, how to evaluate an index and the conventions of indexing.

The Society’s online training course is a self-study programme that leads to professional accreditation, preparing students to work as professional indexers. Assessments, tutorials and support from experienced indexers help students progress through the course modules.