Originally Posted by wallcraft
TOPAZ ebooks are created for the Kindle by Amazon on behalf of the publisher. This means that is usually isn't available in any other format at other ebooks sites. I have seen a few TOPAZ titles being replaced by MOBI later on, but if you buy the TOPAZ you don't get the MOBI to replace it (the MOBI is a different ebook in the Kindle catalogue).
A simple way to check is to do a multi-site ebook search, for example AddAll
. This won't distinguish between TOPAZ and AZW for the Kindle, but will tell you if it is available in other formats.
Be aware, though, that some Adobe DRM'd PDFs and Sony Store LRXs are available in the Kindle store as Topaz format books. I've noticed this with some books that contained substantial sections in Arabic; PDF can display them just fine, but the Mobi alternative is to supply these sections as images which doesn't work all that well in practice.