The Untethered Soul by Michael A. Singer is a spiritual self-help book that guides readers to inner peace by understanding that they are not their thoughts or emotions, but rather the consciousness that observes them. It teaches how to let go of the ego and the inner monologue to achieve freedom, happiness, and spiritual growth by becoming a mindful observer of your own mind. The book uses practical, spiritual, and philosophical insights to show how to live a life of joy and fulfillment that is not dependent on external circumstances.