There are many many many dare I say WAY too many marketing books out there in the world. The ones I have been reading lately have always been suggestions from other indie authors, but I find them to be lacking. Most of them not even worth the credit on audible as they can be less than 3 hours long.
So naturally, I have a Spotify profile so I can have a playlist for my books, characters and the Mississippi River pack in general. I have always enjoyed working while listening to music, and I know that this isn't a brand new concept for authors, but it's still very fun.