The book, The Overthinking Cure by Nick Trenton, is a self-help guide focused on reducing stress, anxiety, and overthinking by teaching readers how to cultivate a proactive mindset and develop greater psychological flexibility. Trenton emphasizes the importance of being present, accepting what cannot be changed, and reframing negative thoughts. He introduces techniques like mindfulness practices based on Acceptance and Commitment Therapy (ACT) and cognitive restructuring to help readers become more aware of their automatic thought patterns and consciously choose different responses. The book also delves into the concept of non-duality, a Buddhist principle that suggests acceptance of the world as it is, without judgment or division, as a path to lasting peace and contentment.