
You may find EPUB books downloaded from torrent sites or converted from another format are filled with spelling or formatting errors, which makes the reading experience very uncomfortable. This guide will tell you how to edit EPUB files with free Sigil.
About EPUB
EPUB is actually a compressed file, which (the extension EPUB) can be directly changed to "zip". Once decompressed, there will be generally 2 folders and 1 mimetype file generated. The content files (HTML or XHTML) are saved under ops / xhtml. If you are familiar with HTML language, you can directly use any editting tool, such as Dreamweaver, to edit the HTML / XHTML files.
About Sigil
Sigil is a powerful EPUB editor supported on multi platforms: Windows, Mac and Linux. It can be used to not only edit EPUB files but also create EPUB books.
Edit EPUB files step by step
Make sure to download the correct version on your computer (with "Featured"). Here I take Sigil for Windows (the third item) for example.
2 Install Sigil on your computer.
Uncheck "Associate ebook files with Sigil" and "EPUB" on the "Select Components" screen. Or every time you open an EPUB file, it will be opened with Sigil by default.
3 Open your EPUB book with Sigil. Right-click the book, select "Open with" -> Sigil is a ...
4 When the EPUB is opened, the cover page will come in front of you. All content pages are listed under the "Text" folder on the left-hand side.
5 Double-click each html / xhtml content page to open and edit. You can edit the EPUB files like other editting tools, such as MS word.
The icons on the upper tool bar are easy to use as well.
6 Click "Tools" -> "Metadata Editor", you can manually edit the EPUB information / metadata.
Besides "Title", "Author", you can click "Add Basic" or "Add Role" button on the right-hand side to edit more metadata.
After finishing editting one page, you'd better close the corresponding page tab. Or Sigil might crash due to a shortage of system resource. The closed page will be saved automatically.
7 When all editting is done, click "File" -> "Save" to overwrite the original. Or select "Save as..." to save as a copy.
Conclusion
Sigil delivers an easy way for users to edit EPUB files manually, although the whole editting progress is a bit slow. If you know about HTML and CSS, a basic editting tool like notepad, would be enough.

Ada Wang works for Epubor and writes articles for a collection of blogs such as ebookconverter.blogspot.com.
I am using Sigil and can not find this file anywhere in the epub.
Can you help me?
Thomas Neviaser