Sorry, but the author is suspect.
Does it have to be in ebook or is it available in other formats, pdf, etc?
I could ask my tech gurus about other formats.
It's definitely possible to convert mobi and ePub into PDF. For example, someone could use Calibre which is an excellent and free app.Also, in case people don't already know, even if you don't have a Kindle or other ebook reader (e.g. Nook), you can still read ebooks on your desktop, laptop, iPad, etc. Just download the Kindle application for your PC or Mac or whatever. That's how I read ebooks.This way you can read all sorts of free ebooks without necessarily owning a Kindle or Nook. There are lots of classic books available online for free including many Christian ones. Feedbooks and Project Gutenberg are a couple of great places to find free ebooks. Amazon has a lot of free ebooks as well.
While we're on the topic, Andy Naselli and Tim Challies have recently provided lists of helpful apps they use. Not to mention Challies is currently giving away a Kindle.
God's Canon also available in HTMl format on Monergism.comhttp://www.monergism.com/thethreshold/articles/onsite/godscanon.html