Seems there is only a PDF version? I'd suggest to add an epub and/or mobi version: Much easier/better to use on mobile devices and tablets. Of course, it is possible to convert a non-DRM PDF for customers, but it's a hassle. Moreover, you could think about publishing on bigger platforms (Amazon, Apple, Smashwords or even Leanpub) as well: that might increase reach. Perhaps lower the price to 9.95$ in that process - that way you'd get 70% from every sales through KDP (35% else).
