This is a custom Kindle dictionary for the series. It makes looking up Dune terms as easy as looking up other words from your Kindle's default dictionary. After buying, you simply need to get the dictionary on your kindle (two potential ways are over USB or emailing it to your Kindle's email address) and then it acts as a built-in dictionary. Depending on what version software your Kindle is running, you may need to change your default dictionary to the Dune Dictionary.
When I read Dune on my Kindle Paperwhite I was constantly trying to look up words in the provided glossary. This is a miserable experience on a Kindle. Navigating to the glossary and then flipping pages to where the word should be takes forever. It is even worse when you take all that time and the word isn't even there. Either way you are completely disrupted, removing you out of the rich universe created in Dune.
About 30% of the way through the book, I was sick of doing this and ended up printing off terms from Wikipedia. Looking up words on printed sheets of paper was a pain but it was faster than looking up words on my Kindle. This still wasn't time efficient and now I had to carry around a stack of reference papers.
About 40% of the way into Dune I was fed up and took some time to research how to create a custom Kindle dictionary. This is the result of that work.
The difference between reading Dune without this dictionary and with it is like the difference between struggling to survive without water and having water to spare. My enjoyment of Dune (and the following books) skyrocketed once the barrier to looking up words was reduced to effectively nothing. I wish I had created this dictionary when I first grew frustrated with looking up words (which was shortly after beginning the book).
I've found this dictionary useful when reading all of the Dune novels. Personally, I think this dictionary made reading Dune enjoyable and would have easily paid three dollars for it. Instead of charging three dollars I'm setting the minimum price low, at one dollar, because I want this to be available to everyone. I wasn't able to immerse myself in Dune before I created this dictionary and I don't want price to hold anyone back. If you feel like paying more you have the option. Dune is truly a terrific book (and series) that unfortunately is painful to read on modern devices.