Feature Spotlight: Pop-Up Footnotes

In our ongoing quest to bring our readers the most important new features to make the reading experience easier, prettier and more intuitive, Penguin Random House is in the process of introducing pop-up footnotes across our reflowable eBook range.

In the past, when you touched or clicked a footnote in an eBook, you’d be taken to the end of the chapter or the back of the book to read it, and then have to click another link to return back to where you were (or somewhere close to it). It was a nuisance when reading, especially in books with significant numbers of footnotes (Pratchett fans, we hear you!) and it’s long been acknowledged that something needed to change.

When the latest version of the official EPUB spec (EPUB 3) came along, it introduced a specification for footnotes to appear as pop-up boxes, which was great – but as with anything in the EPUB spec, it was up to the companies making the e-readers and e-reading software to implement the feature. Very few did, and of those that did introduce pop-up footnotes, their exact implementation varied widely, and getting it to work on one platform often broke it on another – so until now we’ve been unable to roll it out.

However, recently the Penguin Random House eBook tech team got together and finally worked out a method to get popup footnotes working across all major platforms, with an elegant fallback for software that just can’t support pop-ups. We’re now able to offer pop-up footnotes on many platforms including Amazon Kindle, Apple iBooks, Google Play Books and Kobo, with a single file and single block of code (read: magic trick) that allows pop-up footnotes to work across all those platforms, without having to create ‘custom versions’ for any specific vendor.

This won’t appear immediately on all older eBooks (except for on Kindle, where it should already be appearing), but we’re introducing this in stages and you’ll start to see it more and more on new titles as time goes on.


  1. Hi,
    nice feature! How do I know which books from Penguin support it?

  2. Another question,
    I’d like to test it on the reader I use. Is there a free sample I could try?

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