Ryūnosuke Koike is a Japanese Zen Buddhist monk and author who serves as the resident monk at Komyoji Temple in Kamakura, Japan. He is best known for his international bestseller *The Practice of Not Thinking: A Guide to Mindfulness and the Art of Letting Go*, which introduces Zen meditation principles to general readers. Koike's writing bridges traditional Zen Buddhism with contemporary mindfulness practices, offering practical guidance for reducing mental clutter and finding inner peace. His approach emphasizes simplicity and accessibility, making ancient Buddhist wisdom applicable to modern life. His work has gained widespread recognition in both Japan and internationally, particularly among readers seeking practical spiritual guidance.