Best hypnobirthing books?

I'm 14 weeks and starting to think of labour! Would really like to go drug free - I have a hypnobirthing app but not sure how good it is. I'm looking for a book or any other resources that are meant for beginners. Please let me know what you've found helpful, would also love to hear any positive birthing stories! Please no horror stories, I've heard so many already and right now I'm trying to keep my mind focused on the positive right now. Thank you!