I would dearly like to know how to do that, since I have been trying for years to download the Kindle books I have on Amazon to a local (linux OS) computer and the site will not allow it, stating that they can not identify a Kindle device to download to.
Finally gave it up as a Lost Cause. :(
As far as that feature is concerned, Amazon is as helpful as a Bangladesh Computer Repair and Chicken Currie Recipe website.