So what’s an e-book file then? What program do I open it in? Why can’t I edit it? What’s the difference between an e-book and a kindle and an ePub?
An e-book is just an electronic book – any ‘book’ that you can read on your computer or an e-reader is an e-book.
An ePub is a type of e-book. They can be read on computers using programmes such as Adobe Digital Editions, Kobo desktop, Calibre etc. You can also read them on iBooks on the iPad, Kobo app or readers, Nook (in the US) etc.
Kindle is the Amazon reader. The e-books you can read on them often get called kindle books, but the file format is really what used to be known as mobi. You can read them on any Kindle app, or a Kindle reader or in a program like Calibre, which is also a conversion program (but that’s another story).
The reason you can’t open an ePub or Kindle/mobi file on your desktop and edit it like a Word file is that they aren’t really files at all. They are a zipped-up collection of files, similar to a website. In the case of ePub files, if you change the extension to .zip (PCs only) apparently it will miraculously unzip to show you this collection of files. I don’t know if this works because I don’t own a PC, and I would suggest if you try it you do it with a copy, because you might not be able to zip it up again. But I have a script on my Mac called EPUB zip that does the same thing. If I drop an ePub file on to it this is what I end up with:
Epub unzipped folder
Just a quick run through of these files: The files at the bottom with .xhtml endings contain the text of your book – one file per chapter (if you have set the files up that way) – you can edit these files using a text-editing program. I use a fantastic and free program called Textwrangler and sometimes Dreamweaver. The doc.ncx file is where the clickable table of contents is. Images go in the image folder including the cover image. Fonts go in the fonts folder (er – obviously). The css folder contains the css files (cascading style sheets) that style the text (bold, italics, that sort of thing). The OEBPS folder contains the content.opf file. This file is a packing list – all the files that make up your ePub must be listed in this document, along with essential metadata and the instructions the e-book reading software needs to display the book properly. The META-INF files contain a load of required gubbins, but generally you shouldn’t have to open them at all.
When I’m creating ePub files I do all my formatting in Indesign, then export to ePub and unzip, edit and zip them back up again. Then it’s crucial to check the files on as many apps and e-book readers as possible. Check that the table of contents works, check at different text sizes, different fonts (if available). Check that your formatting hasn’t been lost. Phew – loads to do…
And with that, off to cook dinner.
To be continued…