libebook is a library to read metadata and content from ebooks (unprotected epub and mobi books only).
Mobi support is based on the MobiDoc class in SumatraPDF's code.
The original files are distributed under a Simplified BSD license, my files are under the GPL3 (see COPYING).
The library comes with two example tools:
bookdump <ebook> <outdir>
and
bookinfo <ebook>