All spiritual traditions mandate harmlessness, yet the twentieth century was the most violent period in human history. How is this possible? Positive Harmlessness in Practice documents that we have no collective experience of harmlessness because our habits of harm are so pervasive. To build our “harmlessness muscle”, Dr. Riddle details a pragmatic three-step daily practice-a Butterfly Shift. Such mini-immersion experiences of harmlessness help us develop the skills and habits that make it possible for us to embed harmlessness as our core value. Positive Harmlessness invites us to embrace an ethic of harmlessness, individually and as a human family. Practical exercises and a Harmlessness Scale help us learn to model harmlessness in all that we think, say, and do.