When Amazon first introduced Kindle, way back in 2007, they said it did not support indexes. In 2011 this has not changed – the Formatting Guide at Kindle Direct Publishing says, under Creating Back Matter:
Back matter consists of the last pages in your book which provides additional information the reader should know about, such as Bibliographies, Appendices, Notes or Glossaries… Indexes are not recommended at this time.
Kindle Direct Publishing
Following that advice, when publishers started putting books on Kindle back in 2007 they often simply excluded the index, even when it existed in the print version. That practice has since changed, and now they tend to include the index, as it appears in the printed book, but with a caveat at the beginning saying that the reader should use the search facility to get from the index entry to the relevant passage in the book.
It is possible to include hyperlinks in a Kindle text, just like a webpage, creating a jump from one point in the text to another. At least one book formatter tried to use hyperlinks to overcome the index limitations by linking the index locators to the start of the page they referred to. This is very quick to do (just a matter of minutes) but doesn’t produce a very satisfactory result. The problem is that Kindle pages are not only small, they are variable. Readers can change between 8 font sizes, change the typeface, line spacing, words per line, and even rotate the screen, all of which drastically affects how much appears on a page. So if the original printed page was quite large, and the font small, say a page of endnotes, and the Kindle reader chose a large, easy-to-read font with generous spacing, it might be that one printed page covered 12 or 15 Kindle pages. Think what that means. The index says that the information is to be found on page 137, and the link takes you to the top of the printed page 137. If the relevant text is actually at the bottom of page 137, then the reader has to read through 15 Kindle pages of text before they find what they are looking for.
On 7th February 2011 Amazon announced that they were introducing ‘Real Page Numbers’ to the Kindle. This development, which has now been rolled out to everyone’s Kindle via software updates, means that it is possible to press Menu, enter “137” and press “page”, and be taken to the text position in the Kindle which matches the top of page 137 in the physical printed book, assuming one exists. This is actually better than the linking mentioned above for two reasons. First, it is much quicker to use the GoTo function than to navigate across the screen using the arrow keys to reach the link – remember there is no mouse or touch screen on the Kindle. Second, it requires no special linking from the book publisher, so it can work for books from the back catalogue which have indexes. However, it still suffers from the problem, described above, that the page size does not match. There is no way of knowing where the print page ends on the Kindle – it could be three pages away or fourteen-and-a-half.
The only real solution is to link the index locator directly to the relevant character position in the text. Hyperlinks can do that but it requires that the indexer has put in the extra work and has specified precisely to where on the page the index entry refers. This can have been recorded using embedded indexing, or some form of XML indexing, but the extra work must have been done. To demonstrate that it can be done, I have, for the Society of Indexers, formatted for the Kindle their book, Occasional Paper 5, Indexing Children’s Books complete with a hyperlinked index. (Available from Kindle Store UK US DE)
This allows the user to go from the index to the correct text with a single click, and return to the same position in the index by pressing the Back button.
Some publishers who use XML and already require indexers to produce linked indexes will readily be able to produce indexes linked in this way, but what is still unaddressed is how the reader gets to the index. The Contents is a special button in the Goto menu, but the Index is not there. This is because Amazon say that the Kindle does not support indexes. In fact, a simple software change would appear to be all that is required and usable indexes will be possible. Of course, some indexes will be not linked by the publishers and others will, so some indexes will me more useful than others – but that is nothing new.