Sigil 0.9.14

The epub file format is notoriously difficult to edit. It's not just text with occasional pictures like txt or doc files, it's also loaded with special file formats and features that those file formats simply don't support. What you need is a specialized program dedicated specifically to editing epub files, and Sigil promises to be just that.

While you're installing, there's an option to associate this program with epub files. I highly suggest doing that, as you can always redo the file association later on, and odds are you downloaded Sigil because you'll be using it frequently in the foreseeable future. You can also associate it with txt and html files if you'd like.

Sigil's interface is nicely divided. The main view is divided into three resizable panels. The table of contents panel is on the right, the book browser is on the left, and a tabbed document view is in the middle. You can rearrange these panels any time you like.

The actual editing process takes some effort to learn. It codes like an HTML file, or XHTML documents. This gives it a learning curve for anybody not already familiar with the language. Thankfully, it has an automatic cleaning tool and a help button that has an in-depth tutorial. The user interface also shows a ton of other features such as auto cleaning and validating, as well as error checkers. These features will help you avoid errors in your programming. If you need to edit epub files, you can't really go wrong with Sigil!