The Valkyries feels like you might be reading something important or valuable on the surface, but if you dig deeper it's just a mess. When I got to two thirds of the book I was seriously thinking of abandoning it, but there weren't that many pages left so I was curious to read the ending. Hence, I rate it 2 stars. Now, I want to discuss the content, so beware of spoilers.
I’m sorry, but to put it bluntly, this reads like philosophical musings in a post-nut clarity. I don't need Coelho for that, because I can come up the same musings myself. There was nothing profound or transformative that one hasn't heard on a reel today. It was even ridiculous at moments.
Although Coelho is probably trying to bring back spirituality in people--what is actually spirituality?--these are New Age practices that want to ditch the canonical teachings. Instead of conforming to a traditional, mainstream faith, he concocts inconsistent spiritual musings that in theory should serve the same purpose, but in practice are a differential diagnosis of the moral, spiritual and religious decadence of the contemporary person.
Coelho is writing about mutually inconsistent and poorly explored topics, themes and characters. What do the Valkyries have to do here, warriors in Norse mythology, with the desert mysticism of the American Southwest, the four elements of paganism, and figures like Archangel Michael and Mary of Egypt, characters of Christian mythology. Taken together, these elements have weak thematic connections, and the characters' arcs do not unify them in any meaningful way. If someone wants to sound esoteric, countless such combinations will work just the same.
Long story short, the leitmotif of the book is that of spiritual enlightenment. Every day we have rituals that we need to break off, like going to jobs we hate, or staying in a dysfunctional, sexless marriage. We have made a deal with loss, with failure and we need to stop that. But, we also need symbolic acts that will break us free from those chains and commit to personal transformation. We need to find our agency and help our guardian angel to lead us on our path. They don't manifest literally in front of us, but we acknowledge their presence through coincidences, and other people's help when we are in need, just like a deus ex machina.
I'm not sure if Coelho writes about this literally or figuratively, but I am giving him the benefit of the doubt. There is evidence that chemically induced altered states of mind like with ayahuasca, LSD, or mushrooms do have therapeutic effects and people report spiritual experiences, but this book didn't achieve its goal.