"For many years, I have been a student of spirituality and states of consciousness. For many more years than that, I've been a student of dogs," says best-selling author Jean Houston, whose study of this subject is the basis of "Mystical Dogs." Houston has spent a lifetime bridging the worlds of animals and humans, exploring a realm that pet owners have glimpsed and indigenous peoples have known for millennia. The author identifies dogs, with their deceptively uncomplicated, joyous, loving nature, as "custodes animi," guardians of our souls. She shows how animals, particularly dogs, are often the best spiritual teachers. For example, in Houston's hands, a seemingly simple story, such as a man saying goodbye to his beloved dog, becomes a striking metaphor about personal and planetary transformation.