Free and open source software under GPLv3 Multi-platform:
runs on Windows, Mac, and Linux (note Linux only receives limited support) Full UTF-16 support EPUB 2 spec support with limited EPUB 3 support Multiple Views: Book View, Code View and Preview View WYSIWYG editing in Book View Complete control over directly editing EPUB syntax in Code View Table of Contents generator with multi-level heading support Metadata editor User interface translated into many languages Spell checking with default and user configurable dictionaries Full Regular Expression (PCRE) support for Find & Replace Supports import of EPUB and HTML files, images, and style sheets, Documents can be validated for EPUB compliance with the integrated.
All imported files have their formatting corrected, and your editing can be optionally cleaned Plugins!