The synopsis and 5 star review of this book are certainly accurate, but in this review I must stress a different point of view.
This is most certainly a book about a spiritual journey, and a philosophical one inspired by writers, poets and philosophers. It is also a book purportedly about nature, or it has been descibed as nature writing. This is only true so far as it seeks to conform to an idea of a literary tradition. In truth this book, and Perrin's style, are deeply problematic. I found that it was far too personal, it dwelt too long on one man's narrow and compromised view of nature, and the way he placed those views onto it. There is also an assumption of spirituality and nature that is, philosophically, less than rigorous.
Overall, I found that the reasons the previous reviewer liked the book, are also more than capable of being its major stumbling blocks. If you want a safe nature text that relies heavily on literary quotations; that tries to live up to the worn-out philosophies of Thoreau; one that assumes religion and nature are symbiotic, then by all means buy it.
If you want a mature, rigorous, impartial, and studied nature book, then look elsewhere (Kathleen Jamie's 'Findings' is probably the best place).