1) I think there's definitely not enough contrast between the lettering and the background, so I think it would melt into the bookshelf. And it definitely wouldn't be legible in thumbnail size.
2) I think the above subtitle text is too narrow, so it's difficult for me to read, even on my computer screen. (And I don't require glasses).
3) As others have said, it looks like she's holding a blueberry to her heart. This strikes me as odd, but it looks nice.
4) The design around the blueberry is very elegant. I like that a lot. I also like what you've done with the woman.
The design would certainly get me interested in you as a graphic designer, because it shows you know what you're doing. But I think the typography needs work.
That being said, it looks professional. I don't think this is the kind of book I would read, because it looks like too edgy / romance for me. But I do get a scifi / cyberpunk vibe, definitely. That might be amplified if you did something electric / neon with the central blueberry.