Used this to go from my handwritten book, to a beautiful (in my eyes) cross platform eBook. Now just need to bet over my self-consciousness, finish up editing, and get it self-published!
Vellum is a really solid great app, made by two engineers ( @Bradandalman & @Bswest) that helped create the story telling software that got Pixar's stories to the world.
LongShorts Stories