that will also allow you to generate another version for kf8.
For that I will need the spec of both. I thought it was pretty closed, but maybe there are some pointers.
I don't think anyone other than Amazon (well, maybe Calibre) tries to directly generate mobi files. Rather, what they do is create an epub file and then feed that to kindlegen to create the mobi file. The epub in turn ideally contains some Amazon-specific tweaks, primarily to get the "Start" and "TOC" tags right. Amazon has been incredibly sucky about publishing actually useful documentation about what they actually support or don't support in their flavor of "epub." But what they have published (and not all of that is correct) can be found at: http://www.amazon.com/kindlepublishing mobiread and other forums including DP have insights (and flames) Someone somewhere *does* understand mobi internals, see for example "mobiunpack" a python script which turns mobi into epub. Search http://www.mobileread.com on "mobiunpack", also http://wiki.mobileread.com/wiki/Mobi_unpack . [These tools only work on non-DRM -- they are not piracy tools.] Then the epub derived from the mobi can be examined using Sigil for example. This is useful, for example, to try to reverse engineer what the epubmaker chain is actually doing to your code, so that you can try to work around the epubmaker transformations. See also: http://wiki.mobileread.com/wiki/MOBI -- if, god forbid, you insist on bit-twiddling yourself.