The way that Atlantis does this is to incorporate the free Kindlegen utility from Amazon. This is a utility that converts .epub and html files to .mobi. I was already using the Kindlegen utility occasionally as a command-line tool to produce a .mobi file for the Kindle. Most of the time I was using Calibre, another free utility, to do conversions. Naturally, Atlantis is my primary resource for .epub production, because it does such a great job.
It is great to have the .mobi feature incorporated into Atlantis, so that it is not necessary to use the command line to run Kindlegen (it was a bit cumbersome, and I am a guy who did that kind of thing routinely back in the DOS era).
If you do not have a .mobi/Kindle viewer, you can download the free Kindle Previewer at:
http://www.amazon.com/gp/feature.html?i ... 1000765261
It is easy to use and has a nice, crisp appearance. Just as an FYI ... You can also use the Kindle Previewer to view an .epub. It converts the .epub to .mobi by using the Kindlegen utility. I am not going to check this out ... but I think that you automatically install another copy of Kindlegen on your computer when you install the Kindle Previewer. The copy of Kindlegen that Atlantis uses is located in the Atlantis folder.