Book metadata is a vitally essential ingredient in book marketing and discoverability.  If you are a relatively unknown author, then producing good quality metadata is just as important as producing a good quality book.  Without it, your book will languish in obscurity, no matter how great it may be in every other regard.  But what IS book metadata, and how do you best use it to your advantage to publish a successful book?  This ultimate guide is going to look at what book metadata is, why it’s so important, and give you some practical tips on how to best put metadata to work promoting your book.

So, let’s start at the beginning and answer the burning question of what the heck is book metadata.


What is Book Metadata?

Book metadata is what distinguishes your book from everybody else’s and any other book(s) you might publish in the future.  As a whole, book metadata covers a vast array of nearly 4,000 individual data points ranging from various types of classification, contributor information, content descriptors, and specifications.  Thankfully, there is a huge difference between the amount of metadata you can create versus the amount of metadata you should create, as illustrated in this graphic from “Metadata Essentials” by Jake Handy and Margaret Harrison.

Book metadata use I the publishing industry.
Book Metadata use in the publishing industry

As for where book metadata sits in the grand scheme of things, it acts as a filter between what you as the author/publisher (as well as any aggregators or distributors that you use in getting your book to market) create and what consumer-facing channels such as retailers and libraries present to their users (both online and offline) to help them make buying decisions.


Why is Book Metadata So Important?

In this current day and age where the majority of books are sold online, metadata acts as a means of bringing your book to life and allowing potential readers to better judge whether your book is right for them.  

Think back to the last time you went to a library or a physical bookstore looking for your next read.  You would have had the opportunity to walk up and down the aisles, stopping at genre sections that you had an interest in and browsing through the book jackets looking for something that piqued your curiosity.  You’d then pick a book up off the shelf and read the back cover blurb and maybe the author bio; you might have even flicked through some of the pages and glanced at the table of contents if it was non-fiction – just to make sure you were getting the information you wanted. 

Now compare that experience with shopping for a book online.  You don’t get any of those interactions with a book before you buy it.  That’s where book metadata comes in.  Really good metadata answers all of the questions that you are subconsciously asking when you perform all those little tasks in a bookstore or library when deciding what book to buy.  It helps the reader to anticipate what he or she should expect when they receive your book in the mail. 


How Book Metadata Works

When it comes to selling books online, book metadata and discoverability go hand in hand.  To the average self-published author, metadata works in the same way that SEO does for a website; it enables people who have not heard of you or your book to learn about your books’ existence and then help them decide whether your book is right for them.  To understand how book metadata works, you need to have a basic understanding of how book search engines, like those used on Amazon, work.

Amazon employs an automated search algorithm, similar to that used by Google, called A9.  However, unlike Google’s algorithm which is designed to provide the most accurate answer to a question, A9 is designed specifically to provide the best product for a situation and ultimately to make you buy as much as possible.  As such, an Amazon search will not only bring up products that are relevant to your search but will also rank those products according to what it thinks you are most likely to buy based on several different factors such as click-through rate, conversion rate, overall sales, and keyword relevance.  Because Amazon’s ultimate goal is to make as much revenue as possible (not only short term, but long term as well), they not only want you to buy, but they want to make sure that you will be satisfied with your purchase so that you will come back.  As such A9 also takes into account other factors that algorithms like Google don’t such as reader reviews, product image quality, bestseller status, and participation in Amazon features (i.e. Look Inside, Kindle Unlimited, and other Amazon programs).

It’s important to understand that an automated algorithm like A9 is a distillation of all of these factors combined, so you won’t always see a direct correlation between changes to your metadata and your Amazon search rankings.  But by familiarizing yourself with these factors and applying best-practice techniques to the book metadata that you produce; you will give yourself the best chance of increasing your books’ SEO and potential sales.

That being said, one of the most important ways that you boost your books’ SEO is to create great metadata that contributes to click-through rate and ultimately to sales.  So, without any further ado, let’s take a look at the essential book metadata that you should include with every title you publish and give you some pointers on how to maximise each metadata field.


Book Metadata Essentials

Remember how I mentioned earlier that there are nearly 4,000 potential data points that you could include in a book metadata set?  Well, to make things easier for you, here is a list of the metadata elements that your book should NOT leave home without.  Nail these, and you’re well on your way to giving your book the best chance at success.

  1. Title, Subtitle & Edition
  2. Contributors
  3. Contributor Bio
  4. Series (if applicable)
  5. Description
  6. Category & Subject Codes (aka Genre)
  7. Keywords
  8. Format
  9. Review Quotes
  10. Audience Code
  11. Age Range (if applicable)

Let’s look at each data point individually in more detail…


Title, Subtitle & Edition

A books’ title is your first chance to make an impression on your reader, so be sure to give careful consideration to the title you choose.  Some authors make the mistake of thinking that if they title their book similarly to another more famous title that it will help improve discovery, but this is not the case – your book will get buried below the more famous versions and readers will potentially miss your book completely.  So be sure that your title is as distinct and unique to your book as possible.  

If the title you wish to use is a bit close to the title of another publication or book, then use the Subtitle field to add distinction.  A subtitle should add clarity to the main title but should always be listed as a separate data point – never combine them, even if they appear together on your cover artwork.  It is also good practice to include relevant keywords in your subtitle if possible but avoid forcing keywords (also known as keyword stuffing) simply for the sake of SEO as it could confuse your reader.  It is also worth pointing out to not include any series names into the subtitle field if your book is part of a series; this has its own metadata field that is separate which we will cover shortly.

Lastly, if the book you are publishing is an update on a previously published title, then be sure to include edition information.  This ensures that readers are aware of which is the most current version and what has potentially changed from the last edition.  The Edition metadata set includes Edition number, Edition type and Edition description.

Pro Tip: Keep your title to fewer than 80 characters (including subtitle) so that it’s optimised for mobile browsing.



Including a detailed Contributor section to your book metadata allows for a more immersive and interlinked search experience for your readers.  Not only can they then find other books that you have published or been involved with, but they can also find books relating to other contributors involved in your book.  For example, if a reader loves the illustrations you used in your book and you included your illustrators’ details as a contributor, that reader can then find other books illustrated by that same artist.  Because of this, retailers like Amazon love to see a more robust contributor dataset than just author name.

In addition to simply listing all of the contributors to your book by first and last name and by the role they played in your book (i.e. author, illustrated by, edited by, cover designed by, etc.), it is also beneficial to include location data for each contributor so that readers can then find titles by local authors.

Pro Tip: Be sure to include all of the names from the cover or title page and be consistent with spellings and presentation (for example J.R.R. Tolkien or Dr. Rangan Chatterjee).


Contributor Bio

A contributor biography is recommended for all listed contributors but should be considered essential for the author and any co-authors.  These biographies are frequently shown on retail listings to provide readers with a bit of background on the author and to make them more relatable.  A good biography should be brief but packed with notable facts and achievements such as relative credentials or experience, prior work or awards, related associations or affiliations, and any other activities and information that a potential reader may find interesting.

It is recommended to use HTML markup in your biography to highlight important points or works for the reader.  You can include website addresses for the reader to conduct more research should they wish, but you want to avoid including any active hyperlinks to those websites that might temp readers to click away from your book listing.

Pro Tip: Keep biographies between 50 and 250 words for each contributor and avoid using external links such as blogs or author websites (you don’t want to pull potential buyers away from buying your book).


Series (if applicable)

If your book is part of a series, then it is imperative to inform the reader of that fact by listing the series name and number as part of your book metadata.  These details can be added retrospectively if you publish a book with the intention of it being a standalone work, but then add other titles to the series in the future.  

It is also important to include the series number to each book where the order in which the books within the series are to be read is important (for example with fictional trilogies).  However, if the order of books within a series is not meaningful, then this dataset can be left blank.

Just as the subtitle should never be included in the title field, the series name and number should never be included in the subtitle field.

Pro Tip: If your book is part of a series, then be sure to tell your readers about it every chance you get.  If they enjoy the first book; they’ll want to buy the rest.



Consisting of both a long and short version, your book description should be an accurate, compelling and comprehensive breakdown of what a reader can expect when they buy your book.  Here’s a brief anatomy of what makes a great book description:

Headline – start with a bold first line. Make it punchy and attention-grabbing.  This is the basic elevator pitch for your book and is critical for SEO. It also acts to hook a potential buyer into reading more.

Exposition – This is the meat of your description consisting of one to two paragraphs giving buyers the information they need to make an informed decision as to whether your book is right for them.  Include things like who or what the book is about, where and when the is story set, and what happens.  

Close – this is your persuasive “why to buy” paragraph.  Keep it short and sweet and emphasise the value that your book provides. Focus on what they will get out of reading it and why they should buy it now.

The short description should be a single paragraph distillation of all of the above condensed into 150-200 words.

It is worth mentioning that it is very rare for a short and long description to appear side by side, but instead work in tandem at various points of the buying journey.  As such they should be written to complement each other.

Pro Tip: Describe your book in a conversational tone but keep it to between 200-600 words.  A bold opening line and paragraph breaks (coded using HTML) work best to grab attention.


Category & Subject Codes (aka Genre)

Category and Subject codes indicate to potential buyers, retailers and search engines what your book is actually about – the genre, topic or theme that your book covers.  Unfortunately, despite being one of the most important data points to help potential readers organically find your book, it is also the most complicated and confusing to get right because there isn’t one all-encompassing system or standard that is used across the whole of the industry.   

The most commonly used set of subject codes is BISAC (Book Industry Standards and Communications).  It has the widest range of codes available and hundreds of new codes are added to the list each year.  You can view the full list at https://bisg.org/page/BISACEdition. However, Amazon and Walmart (two of the largest book retailers in the world) use their own proprietary subject schema, so you see what I mean about confusing and complicated.

So, in the hopes of simplifying things a bit for you, here is some best-practice advice:

  • Chose one BISAC code as a minimum, but three is considered best to help ensure the broadest reach for your book
  • Order those three codes by the most relevant and important first
  • Avoid using general codes if a more specific or granular code is available
  • Chose subject codes from multiple top-level headings if at all possible, to broaden discoverability

If you want to get a little bit more advanced, or if your book is intended for an international audience, then you can supplement your BISAC codes by adding in additional Thema codes.  Thema is a fairly new coding system that replaced the BIC category codes in 2017.  It is still in its infancy with only about 29% of retailers using it, but it is growing in popularity.  Its biggest benefit is that it was developed for international use as opposed to BISAC which is more North American biased.  Thema schemes can provide an extremely precise subject code as it is broken down into subject categories and qualifiers including national extensions.  To find out more about Thema, visit https://www.editeur.org/151/Thema/.

Pro Tip: Choose 2-3 highly specific categories using the BISAC subject code system.  If you don’t find exactly what you need, then supplement using keywords.



The use of keywords in your book metadata improves online retail categorisation and search engine optimisation by aligning your book with how consumers use the internet to search for things.  While not all retailers actively use keywords in their online systems, Amazon certainly does, so it is worth your while to spend time on this section.

When developing the keywords for your book, always put yourself in your readers’ shoes.  How would they describe your book? What topics do they care about? What words and phrases might they type into Google to find information on those topics? Keywords should be used in a way that most effectively helps a potential buyer to find your particular book, so in short, the more specific the better.

Some other best-practice advice on keywords includes:

  • Don’t waste keywords on author, title, contributors, or other defined metadata points – they’re already searchable
  • Use at least 7 keyword phrases, separated by a semicolon and no space
  • Do not include any quotation marks around keywords
  • Put the most relevant and important keywords first
  • Use keyword phrases that complement (but don’t replicate) the book description
  • The most useful keyword types to consider are:
    • Specific topics that do not have an equivalent BISAC code
    • Core topics and themes
    • Locations and/or time periods
    • Story tone and/or writing style
    • Character types and roles
    • Format or audience notes

Pro Tip: Have a MINIMUM of 5-7 keywords or phrases that your reader would actually use and incorporate them throughout your metadata as well as in the specific keyword metadata field.



Format (or product form) data details the technical specifications of your book so that readers know what to expect to receive when they buy your book.  Are they going to get a paperback or a hardback, if it’s an eBook is it going to come as an EPUB or a MOBI file?  This is the most basic level of metadata and generally a minimum requirement for both physical and digital books.

If you are publishing a physical product, this data also includes information about the accurate size and weight of the book to aid in purchasing, inventory management and merchandising decisions on behalf of the retailer.  Measurements should include height, width, depth (or page count) and weight, and should be provided as a decimal figure (do not use fractions, even if you are providing measurements in inches). 

Pro Tip: Choose the format that is most descriptive of your binding type, such as mass-market paperback or EPUB ebook.  Also, be sure to use a unique ISBN number for each format.


Review Quotes

Including review quotes as part of your book metadata is not a requirement by any retailer, but it is highly recommended that if you have any positive reviews from beta readers or ARC’s (advance reader copies), that you include them in your metadata at the point of publication.  This acts to provide social proof to potential buyers before your book has had a chance to collect reviews submitted by readers.  

Pro Tip: Include 2 to 8 positive review quotes from industry sources, publications and relevant people such as other authors and influencers within your genre or industry.


Audience Code

The audience code is used to help potential buyers and retailers assign a broad audience demographic to your book.  Always aim to use the most correct and specific audience code that best describes your primary audience.

There are two categories of audience code: Trade/consumer and Specialty.  Trade/consumer audiences consist of General/trade for general adult audiences, Children/juvenile for general children’s audiences not related to any specific educational purpose, and Young adult for young and adult and teen audiences again not related to any particular educational purpose.  The Specialty audience codes deal more with educational levels such as primary, secondary, elementary, high school, college or general higher education, and professional and scholarly subjects which also include adult education and second-language teaching.

Pro Tip: Choosing the correct audience code ensures that your title will be merchandised correctly (i.e. general adult, juvenile or young adult).  Also, make sure that your subject codes and audience codes coincide (i.e. young adult audience code with a young adult subject code).


Age Range (if applicable)

The audience age range data points are intended to narrow down the audience demographic even further.  Age range is a mandatory field for either of the children’s or young adult audience codes.  It is also recommended to include an age range for mature graphic novels and other similar works that might be easily confused as children’s titles.

The age range that you choose should be both realistic and as specific as possible – ideally to a 2-year range for children and a 4-year range for young adults.  Your potential buyers will be using this data to determine whether your book is suitable for their children.

Pro Tip: If you chose a juvenile or young adult audience code, pick a more specific age or grade range to target.  Use a 2-year age/grade range for children and a 4-year age/grade range for young adult.


Book Metadata and IDs

I can very much appreciate that when you look at all the various data points that are included in a robust set of book metadata, it can be very overwhelming.  Especially when you start looking at associating contributors from one title with another and relating individual books with other titles, it can all get very messy very quickly.  That’s where the final, overarching data point you need to include in your metadata comes in… Identification codes – in particular ISBN numbers.

ISBN numbers are essential for any publication regardless of format.  It provides the underlying identification for a title within both internal catalogues and external services such as retailers and libraries.  Without it, your book cannot be distributed and sold via retail channels; the sales of those books cannot be tracked, and your book could become entangled and confused with numerous other books with similar titles or other metadata entries.

For more information on ISBN numbers, please see my blog post “ISBN Numbers: Everything You Need to Know” (https://swatt-books.co.uk/isbn-numbers-everything-you-need-to-know).



So, there you have it.  A bit longer than my normal posts, but hopefully, you will find the information helpful when it comes to putting together the metadata for your next book.  If you want to learn more about book metadata and get more specific tips and advice, then check out “Metadata Essentials” by Jake Handy and Margaret Harrison; published by Ingram Publisher Services (available on Amazon).


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