This is Amazon's definitive resource guide for categories and keywords -- per genre -- within their Kindle Direct Publishing program (KDP).
We will warn anyone who is new to the game of self-publishing that categories and keywords make a HUGE difference in the way that your book is indexed within Amazon's search results --> which in turn affects your book's inherent visibility in terms of being seen by readers who are "browsing" for their next read.
Everyone claims that you need a high rank to increase your visibility on Amazon, but that's actually quite backwards thinking: the truth of the matter is that a high rank is influenced by the number of downloads you receive --> which is partly influenced by how readers find your book in the first place. And one of those ways is browsing via keywords.
If you have a questions about keywords and categories, and how to effectively use them, feel free to post them here and we will attempt to help you.