Okay, really take this with salt, because I've only designed one cover. There's a whole lot I don't know about the art form. I'm approaching this mostly as a reader and a painter. So if anyone with more experience has a conflicting opinion, you would probably be better advised to go with theirs. But I wanted to give you my impressions, in case they help.
Let me start with saying as it is, it's rather nice. It's certainly not a case of, "Good heavens, where do I start?" I'm hoping you release it soon, because it looks like something I'd like to read. So in that sense, the cover has already done its job.
Title: Consider a larger font, perhaps. It seems a bit...understated. The text that goes with it is quite good, but I'd consider moving it to the empty black space above your name instead. Then you'd have room for a title that might show up better in thumbnails.
Artwork: You've got three almost identical elements, in a group of three, and there's nothing wrong with that. You might want to try tinting one of the images blue and one amber, though. There would be a visual theme of trying different approaches which could be a useful metaphor for your book. And it would make it more colorful, although you'd have to try it before you decided if it was useful or distracting. I have decent visualization skills, but it could go either way, depending on execution, and the taste of the observer (like so much else).
I think your blurb on the back is excellent.
Hope this helps.