An accessible guide to the practice of red teaming—deliberately adopting an adversary’s perspective to stress-test plans, assumptions, and strategies—showing leaders how structured skepticism, simulations, devil’s-advocate roles, and pre-mortems expose blind spots and prevent groupthink. Drawing on military, intelligence, and business examples, it presents practical techniques for creating independent challenge teams, designing realistic scenarios, and building organizational processes that reward dissent while managing cultural and political resistance. The book argues that routine adversarial testing improves decision quality, reduces risk, and sharpens competitive advantage, and it offers step-by-step advice for embedding red-team thinking into strategy, operations, and risk management.