Index in a Book: Definition, Purpose, and How to Use It

• Nov 20, 2025
• 9 min read

• Tags: Self-Publishing, Traditional Publishing, Writers

Hello Readers and Writers!

Have you ever flipped through a nonfiction book, looking for that one topic you remember reading, but couldn’t find? Or perhaps you’re an author preparing your manuscript and wondering how to make your book easier to navigate and more professional. If yes, then we’ve got you right! 

In this guide, we’ll walk you through everything you need to know to make your book reader-friendly and credible, from what an index is, how indexes improve usability and reader experience, to their types, structure, and even the costs involved in creating one.

What is an index in a book?

A book’s index is an alphabetical list of the important words, subjects, people, places, and ideas included in it, with page numbers indicating where they are referred to. An index helps readers quickly locate information without reading the entire text.

In this guide, you’ll learn what an index is, where it’s found, its types, its purpose, and even how much it costs to create one.

Index vs table of contents vs glossary

Readers can effectively navigate a book by comprehending these elements:

Table of Contents (ToC): Found at the beginning of most books, the ToC outlines their structure by listing chapters or sections alphabetically, serving as a roadmap of their organization.

Index: At the back of every book lies an alphabetized listing of topics, terms, and names mentioned within it, together with page references where these appear in greater depth. This allows readers to quickly access detailed information on any particular subject of their choosing.

Glossary: Commonly found at the back of a book, glossaries provide definitions to complex or technical terms used throughout the text and help readers better comprehend specific terminology.

Where is an index found in a book?

Indexes are traditionally located near the end of books, after sections like bibliographies and glossaries have been presented. It is used to ensure readers can quickly locate them after finishing the main content. Such placement provides convenient access for readers after having finished with their reading material.

What are the functions of indices in books?

How an index helps readers quickly access information

An index provides readers with an organized summary of a book‘s content, making it easy for them to quickly locate specific information. Instead of skimming chapters for answers they want, readers can refer to an index in search of exact pages where topics of interest have been discussed.

Why indexes boost credibility and sales (nonfiction)

An impressive index enhances a nonfiction work’s professionalism and utility by showing thoroughness. It also increases credibility with readers searching for reliable information sources. A well-constructed index also has potential appeal to those readers seeking quick, convenient information sources.

Do short or simple books need an index?

While shorter books don’t necessitate extensive indices, having one may still prove beneficial. An index provides quick navigation between topics or serves as an easy reference guide, especially important features in nonfiction works with few pages to cover!

Types of book indexes

Back-of-Book index (BoB index)

Back-of-Book (BoB) indexes are one of the most frequent types, typically located at the end of a book. They list topics alphabetically with associated page numbers to provide a comprehensive view of their content and facilitate quick navigation of bookshelves.

Embedded index for eBooks

Indexes in ebooks feature clickable links that lead readers directly to specific sections or pages, providing convenience and interactivity while at the same time being compatible across devices and platforms. However, to achieve maximum compatibility, they require careful formatting so as to be compatible across devices and platforms.

Indented vs. run-in formatting

Indented Index: An indented index lists entries with subentries listed directly beneath their primary entry for easier scanning and finding.

Example

Dragons

    Fire-breathing techniques, 103–105

    Habitat, 45–47

 

Run-In Index: Entries and subentries are presented in a continuous line, which can save space but may be harder to read.

Example

Dragons: Fire-breathing techniques, 103–105; Habitat, 45–47

How to search an index in a book (reader tips)

Reading Entries, Subentries, Ranges, and Cross-References

• Entries: Main topics listed alphabetically.
• Subentries: Indented items providing more detail under the main entry.
• Ranges: Page numbers indicating where the topic is discussed.
• Cross-References: Directions to related topics, often marked as “See” or “See also.”

Practical Example Lookup (Walkthrough)

To find information on “dragons” in a book:

• Turn to the index at the end of the book.
• Locate “Dragons” in the alphabetical list.
• Note the page numbers listed next to the entry.
• Refer to those pages in the main text for detailed information.

Common mistakes readers make (and How to avoid them)

Overlooking subentries: Many readers only look at main topics, skipping the indented subentries that often provide more detail or material that is more germane to the issue at hand.

How to Avoid:

• Always look under the main entry for subtopics that are indented.
• Subentries usually refer to examples, persons, or main discussions that are secondary to the primary focus of the discussion.
• If you are doing focused research, the subentries are time savers, taking you directly to the precise issue you are interested in.

Avoiding cross-references: Cross-references act as links to associated concepts or alternative words. Failure to follow the links can lead to the absence of significant relationships in the text.

How to Avoid:

• If you come to “See” or “See also,” do not disregard it as “off topic.” Instead, go to the suggested entry.
• Cross-references are like leads; more often than not, they connect wider topics or the same topics discussed under different titles.
• For research or studying the topic, it is important to have cross-references for richer content on the topic.

Misinterpreting page ranges: Some individuals consider page ranges, for example, 45 to 50, as boundaries that are only the first or last page stated, while in the actual sense, the whole range is the topic under discussion.

How to Avoid:

• Focus on all of the listed pages so as to get the whole argument.
• Scan through the section and look for subheadings, cases, or illustrations that elaborate on the topic.
• With books that have heavy texts, try to use a range of pages to locate multiple mentions of the same concept, rather than aiming for isolated mentions.

How to build an index (workflow & roles) 

When indexing occurs in publishing (timing and version control)

Indexing typically happens after the manuscript has been finalized but before going to print. This ensures that all relevant content is included and referenced accurately.

Why did professional indexers outshine auto-generated lists?

Professional indexers possess extensive expertise in selecting relevant terms and organizing them logically, unlike automated tools, which merely extract terms without providing context or satisfying readers’ needs effectively.

DIY vs. hiring a professional

Creating your own index may seem simple, but it often misses consistency. For example, you might list “Cars” and “Vehicles” separately, while a professional would link them. Professionals ensure clarity, accuracy, and easy navigation for readers.

Step-by-Step indexing process

1. Defining audience terms and synonyms

Determine what terms your target audience might search for and look into synonyms and related concepts to ensure comprehensive coverage.

2. Identify pertinent topics vs trivial mentions

Focus your indexing efforts on indexing significant topics that further the book’s purpose; avoid trivial mentions that do not add anything of value for readers.

3. Create headings, subentries, and cross-references

Maintain an organized index with clear headings and subentries, cross-references to lead readers quickly to relevant topics, and subindexes as needed.

4. Tools indexers use (specialized software) and why this matters

Indexers often utilize software programs such as Cindex or SkyIndex in order to efficiently create and manage indexes, maintaining consistent and accurate processes in indexing processes. Such tools help ensure consistency throughout this step in indexing processes.

Costs and timelines to expect (What to anticipate) 

Typical indexable page pricing (BoB vs Embedded)

Pricing depends on the type of index and its content complexity; back-of-book indexes usually cost less due to their simpler formatting than embedded indexes.

Time of turnaround and scheduling an indexer

Turnaround times depend upon the complexity and scale of a project; to ensure timely completion, it’s wise to schedule your indexer well in advance.

Budget tips for authors and small publishers

• Plan early: To reduce last-minute stress and save yourself the extra cost associated with indexing, set aside enough time and budget early in your publishing process for indexing. Communicate with both editors and designers so page numbers can be finalized prior to indexing beginning; budget 5-10% of total costs towards this stage for planning purposes.

 

• Explore DIY indexing: For short or straightforward books, it can be worthwhile creating a basic index on your own using tools such as Microsoft Word’s Indexing feature, Cindex, or PDF Index Generator. Organize key terms alphabetically before double-checking page references to ensure accuracy. Anything better than no index is certainly better!

 

• Choose professionals wisely: To achieve polished and accurate results for long or complex books, consider employing the services of professional book formatters or indexers if funds permit; look for certified experts, review samples provided by these indexers, and clarify pricing (typically $3-$6 per page). Alternatively, outsource key chapters while continuing the rest yourself.

Quality checklist: what to consider in an effective index

1. Accuracy, consistency, and reader-centric language

Assure all entries are accurate, consistent, and written using language that meets reader expectations.

2. Coverage of concepts not named in the text

An effective index should anticipate topics readers might search for even when these terms don’t explicitly appear in the text.

How to recognize an index that doesn’t perform well?

Format inconsistent entries: Entries should adhere to a consistent format from start to finish.

Cross-reference issues: Failure to include cross-references can make it hard for readers to locate related material quickly and easily.

Overly deliberate entries: Entries should be concise and pertinent; avoid unnecessary details.

In this guide, you’ll learn what an index is, where it’s found, its types, its purpose, and even how much it costs to create one.

A well-crafted index is more than a back-of-book formality; it’s a bridge between your content and your readers. It improves usability, adds credibility, and makes your work truly professional. Whether you’re self-publishing your first book or preparing a complex nonfiction manuscript, understanding how to build (or commission) a great index is an essential skill.

We hope this guide clarified everything you need to know about book indexes. PaperTrue’s professional book editors and publishing experts can help make your book accurate, polished, and ready for global readers. 

Publishing your own book? Read these articles to get more information:

Found this article helpful?

0

0