Footnotes can be a valuable addition to many different types of books, and if you are publishing an academic, scholarly, or formal document then citations are likely a basic requirement that cannot be avoided. Unfortunately, there is currently no straightforward, built-in way to manage either footnotes or citations when publishing on Amazon's Digital Text Platform, no matter what formatting or publication method you are using in your e-book. Luckily, a third-party utility exists that takes much of the pain out of managing both footnotes and citations within your e-book. This utility goes by the name of kindle-notes, and lives at http://www.kindlenotes.net. As kindle-notes currently provides the best, most straightforward method for adding footnotes and/or citations to an e-book, the remainder of this section will focus on how to use kindle-notes, and the <kn:footnote> tag that they provide.
Also keep in mind that as e-books do not have pages, they also do not have page footer margins. This means that it is simply not possible to have true "footnotes" in an e-book, because page footers, in the traditional sense, do not exist. Instead, what kindle-notes actually generates are more formally known as endnotes, notations that appear at the end of a document. However, this is a good example of a case where it's possible to overcome the limitations of the e-reader in a way that replaces them with something even better. The way to do this, or rather, the way kindle-notes does this, is by linking each footnote or citation directly to its associated text. As you have no doubt noticed by now, all of the footnotes in the book are links, which when clicked will jump directly to the text associated with that footnote. Pressing the "Back" button on your e-reader or using the "[return]" link at the end of the footnote text returns you to right where you were before you clicked on the footnote link. These linked footnotes are known as "live footnotes"1, and if you are publishing an e-book, there is absolutely no reason to not use them. Not only are they more user-friendly than traditional footnotes, but live footnotes also enable some new uses that are difficult or even impossible to pull off using traditional footnotes. For instance, nested footnotes are trivial to create and easy for the reader to traverse in both directions, even with arbitrarily deep nesting levels or multiple nested footnote subtrees in a single footnote. Granted, most books will never need such elaborate footnoting capabilities, but it is possible to create such a structure using the <kn:footnote> tag, and nearly impossible to do so (in a reader-friendly way) in a traditional printed book.
When creating footnote or citation links in a document, there are a number of layout, formatting, and other issues to bear in mind. Links need to be positioned properly to ensure that when the reader goes forwards and backwards between footnotes the e-reader is never left in a weird display state. Numbers need to be generated correctly for each footnote and citation in the document, and if a new one is added, then all the numbering needs to be redone. When using citations, all references to a single source should be consolidated so that they share the same reference number. All told, getting footnotes and/or citations to behave in a correct, user-friendly manner entails a massive amount of work. Fortunately, the creators of kindle-notes have developed a tool that will do all of the previously mentioned tasks for you, and a bit more besides. As an author, all you need to know is that anywhere you want to have a footnote or citation, just place the associated text inside of a <kn:footnote> tag. The <kn:footnote> tag was discussed briefly in the Extended Tags section, but it is worth briefly recapping here before moving on to more in-depth topics:
<kn:footnote> - Use this tag whenever you want to create a footnote or citation. The <kn:footnote> tag marks the enclosed text and markup as part of a footnote (or citation). For example:
Here is some text<kn:footnote>With a footnote.</kn:footnote>. Followed by more text.
Will render as:
Here is some text2. Followed by more text.
You've seen this before. The <kn:footnote> tag takes the text inside of it and turns it into a footnote, placing the appropriate links into the document automatically. Note that the <kn:footnote> tag can contain more than just text. You can also place any tags you want inside of the <kn:footnote> tag, including other <kn:footnote> tags. This allows you to add formatting, images, and other embellishments to your footnotes, and even to place footnotes inside of footnotes, like so:
Here is some text
<kn:footnote>With a footnote</kn:footnote>. Followed by more text.
<kn:footnote>And another footnote</kn:footnote>.
Will render as:
Here is some text3. Followed by more text.
Note that the first footnote now contains its own footnote. While most publications will never need to use nested footnotes like this, it is a good example of what can be done using the <kn:footnote> tag. You can literally place anything you want inside of your footnotes, and kindle-notes will handle all the hard stuff for you.
Of course, using the <kn:footnote> tag is only half of the picture. The <kn:footnote> tag is a third-party extension, and is not directly supported by Amazon's Digital Text Platform. Instead, when you make use of this tag, it becomes necessary to allow kindle-notes to process your document before you submit it for publishing. This adds an extra step into the publication process. To have kindle-notes process your document, you must first visit their website at http://www.kindlenotes.net. This will bring up a page with just a couple of basic processing options:
File - There is where you specify the document that you want kindle-notes to process. You should select your e-book's HTML file here. Your document will be sent to kindle-notes for processing, and the processed output will be sent back to you.
Download Output - This options controls whether kindle-notes sends your output as a downloadable HTML file or just displays it as a webpage in your browser. If the box is checked, then you will get a downloadable HTML file containing your processed document. If it is not checked, then instead your processed document will be displayed directly in your browser. In general, if you are ready to submit your e-book for publication or previewing, then you will want to download the output. If you are just trying to do a quick preview to get a feel for how your footnotes will look and behave, then unchecking this option will allow you to immediately see the results in your browser.
Be aware that kindle-notes also provides several advanced formatting options that can be used to control how the footnotes and/or citations that it generates look and feel. Although the default settings should be sufficient for most purposes, it is worth spending some time discussing the advanced options available. To display the list of available settings, simply click the "Advanced Options" link on the kindle-notes homepage. You should now see the following additional options:
Citation Mode - This is the option to use if you are generating citations and not footnotes. It may also be useful in cases where your document references the same footnote multiple times in different places in the text. When "Citation Mode" is enabled, kindle-notes consolidates identical footnotes into a single reference number, such that if you cite your first source five times in different places in your document, that source will receive number "1", and all five locations will reference it as "". If "Citation Mode" was not enabled in that same case, then the first citation would get number "1", and the second would get number "2", and so on, and there would be five entries in the footnotes section for that source, instead of just one. If your document makes use of citations, then you will definitely want to make sure that "Citation Mode" is enabled.
Enable Formatting - This setting enables and disables all the extra formatting performed by kindle-notes. By default, when formatting is enabled, kindle-notes will automatically generate a section header for the footnotes section, and customize the font size and style for the header text and the footnote text. If you do not want it to do this, and just want the footnotes themselves with no additional formatting or content, then you should disable this option. This can be useful if you want to provide your own formatting around your footnotes section, or if you just want to keep things as simple as possible. Unchecking the "Enable Formatting" box will automatically disable most of the other options.
Include Title - This controls whether or not kindle-notes will add a section header to the footnotes section. When enabled, the footnotes will be preceded by a title/header line to indicate the start of the section. The title can be rendered in a different font size and style than the footnotes themselves. If you do not want a title/header in your footnotes section, then you should disable this option. This option can only be configured if the "Enable Formatting" box is checked. Unchecking the "Include Title" box will automatically disable the other title-related settings.
Title Text - This option allows you to customize the text that is used as the title/header for the footnote section. The default text used by kindle-notes is "- Footnotes -". You can edit this to your liking, and also add markup and other formatting tags if you prefer. Note that this option can only be configured if the "Include Title" box is checked.
Title Font - This controls the font that is used to render the title/header text for the footnotes section. It allows the header font to be controlled independently of the footnote font. Here you can specify any font that would normally be available in your e-book, which is to say, anything that you would normally be able to use inside of a <font> tag. The default title font is "Times New Roman". This option is only configurable if the "Include Title" box is checked.
Title Size - This setting manipulates the font-size of the title/header text for the footnotes section. You can use it to make the header text larger or smaller, to your liking. The default title size is "4", which works well if your have written your document using a size of "3" for your normal text. If you have used a different font size, then you may want to adjust this option accordingly. Again, this option is only configurable when the "Include Title" box is checked.
Footnote Font - Similarly to the "Title Font" option, this controls the font that will be used for the footnotes themselves. The valid options are, again, any font face that you would normally be able to use inside of your <font> tags. The default footnote font used by kindle-notes is "Courier New". If you prefer a different font for your footnotes or citations, this is the place to change it. Note that this option is only configurable if the "Enable Formatting" box is checked.
Footnote Size - This controls the font sized used for the footnote text itself. You will probably want to specify a value that is consistent with the font size that you have used throughout your e-book. The default size is "3", which is a reasonable size to use when writing an e-book. If you have used a different size, then adjust this option accordingly. This option can only be configured if the "Enable Formatting" box is checked.
Use Backlinks - "Backlinks" are what kindle-notes has named the "[return]" links that appear at the end of a footnote. This guide makes use of backlinks, so you are probably quite familiar with them by now5. In general, backlinks are a useful feature, and you will want to leave them enabled. One exception to this rule, however, is if you have enabled "Citation Mode". When "Citation Mode" is enabled, the backlink for a citation will always point to the first occurrence of that citation in the text. This can be very annoying for your readers, especially if you cite a source multiple times throughout your text, as every time the reader follows the backlink, they will be taken back to the very first citation for that source. In such a case, it is better to just disable backlinks entirely. When backlinks are disabled, the reader can still return from the footnotes section by simply pressing the "Back" button on their e-reader. This will always take them back to exactly where they were before they clicked on the footnote link, and works reliably even with "Citation Mode". So while backlinks are a generally useful feature, it is often better to turn them off if you have decided to enable "Citation Mode" for your document.
Precise Linking - This option modifies the behavior of the backlinks that kindle-notes generates. With this option enabled, the backlinks will target the line of text the footnote link is placed on. This is a good general setting, and is fairly consistent with what happens when the reader uses the "Back" button on their device. When this option is disabled, the backlinks will instead go to the nearest pagebreak, which in practical terms means the nearest <mbp:pagebreak /> tag in your document. This will give good results if your e-book makes consistent use of the <mbp:pagebreak /> tag and tends to have relatively short chapters/sections. If you do not use the <mbp:pagebreak /> tag, or if you have long stretches of text in between each one, then you will get much better results leaving "Precise Linking" enabled. Note that this option is only configurable if the "Use Backlinks" box has been checked.
Footnote Style - This setting allows you to control the appearance of the footnote links themselves. You can use whatever formatting tags you like, plus the special "$footnote" token, which kindle-notes will replace with the footnote number and link during processing. For instance, the default setting of:
Will render the first footnote as:
If you are using citations instead of footnotes, you may decide that you want to have 's around the citation number. In which case, you might do something like:
Will render the first footnote as:
There are a number of different ways to configure the display of your footnote links. You can get as fancy, or as simplistic, as you like. In general, however, the default display options used by kindle-notes should work perfectly well in just about any e-book.
Footnotes and Images
The problems associated with adding extra manual steps into the publication and/or previewing process become immediately apparent the instant you find yourself needing to publish a document that contains both footnotes and images. MobiPocket Creator cannot process <kn:footnote> tags, and kindle-notes cannot embed your images for you. So it becomes necessary to make use of both utilities every single time you want to submit your e-book for previewing or publication. This manual process quickly becomes tedious, and is entirely too error-prone. Unfortunately, there is no better alternative available at the moment if you need to include both footnotes and images within an e-book. If you find yourself needing both images and footnotes, then follow the following steps very carefully whenever you need to generate a preview of your e-book, and when you are ready to submit the finished version for publication. Note that in this example, we assume that your e-book's HTML file is called "myEbook.html", and that it includes a single image called "image1.jpg":
- Go to the kindle-notes homepage, and submit "myEbook.html" for processing.
- Download "myEbook.processed.html" to the same folder as "myEbook.html".
- Import "myEbook.processed.html" into MobiPocket Creator, as described in Section 5.2.
- Import "image1.jpg" into MobiPocket Creator (if you have additional images, import them as well).
- Build your e-book, again as described in Section 5.2, to create "myEbook.processed.prc".
- Submit "myEbook.processed.prc" to Amazon for processing and/or publication.
Lastly, you should be aware of one minor caveat that comes along with using live footnotes, whether they are generated by kindle-notes or any other tool. By default, Amazon will allow users to download a free preview of your e-book, which contains that first 10% of the document. As live footnotes are really just endnotes with links, any footnotes in your document will not be included in the preview version, and the footnote links will not work (because the link targets are missing). This issue is unavoidable, and it affects more than just footnotes. If you added a Table of Contents section to your e-book, it will suffer a similar fate in preview mode, with any links that point to content beyond the first 10% of your e-book becoming non-functional in the preview version. There is currently no way around this limitation, apart from making note of it in your text itself, or perhaps more appropriately as part of your Foreword or Prologue. It's important to be aware of this issue, and to make sure that people who preview your e-book are aware of it as well, so that they don't erroneously think that your e-book is broken or missing content. In practice, however, this is a minor issue, and it is certainly not severe enough that you should avoid using footnotes because of it. Just know that it exists, and work around it as best as possible.
As tedious as it can be when your e-book has both images and footnotes, they can each add significant value to your publication. A reasonable, though not ideal, way to minimize the amount of extra work involved is to rely more upon previewing in a web browser, and to only go through the full conversion process when you want to proof some major changes, or when you're ready to start proofreading and verifying your completed draft. As important as frequent previewing is to creating a professional, well-formatted e-book, the work associated with doing so needs to be balanced against the benefits gained. When generating each complete preview requires using two separate third-party utilities, it makes sense to preview your work on an actual e-reader a bit less frequently, and to rely upon other tools to help fill in the gaps as best as possible. With any luck, the need to use both kindle-notes and MobiPocket Creator will eventually disappear as Amazon's Digital Text Platform matures and new features are added to it. Hopefully it will not be too terribly long before there is built-in support for image processing and footnotes, which will make using these third-party tools unnecessary. Until then, just follow the steps described above, and you'll manage well enough.
To recap the basics of adding footnotes and citations to your e-book: