I work at Anthemion Software, Edinburgh, and I thought you might like to know that we have made our ebook editor available for free on the Raspberry Pi 2. You can import Word, ODT and Epub files, or write a book from scratch. Jutoh creates Epub 2/3, Kindle (via Calibre on the Pi), ODT and HTML files, and you can add pictures, tables, footnotes, tables of contents, bibliographies, alphabetical indexes and more.
You can download Jutoh here:
It's available in DEB and RPM forms, in addition to a plain tarball with an installation script.
I hope this is a useful addition to the amazing range of things you can do with a Pi.