Five stars because I can't think of anything that would make this book better. I kept a lot of quotes from this book in my reading notes. Doty's writing is succinct; he explains neurobiology and neurochemistry in a way that's easy to understand, and the rest of his prose is sometimes just straight up beautiful. He's so kind to the reader. I think his exercises are really useful and approachable. All the information he presented makes me feel more confident in having a spiritual practice, because the science really does back it up.