This document discusses the use of devil's advocacy in strategic decision making. It begins by defining a devil's advocate as someone who critically argues against an original proposal to test its weaknesses. It then outlines the benefits of devil's advocacy in ensuring corporate strategies consider all perspectives and assumptions. The document provides examples of devil's advocacy being effectively used by John F. Kennedy during the Cuban Missile Crisis and British codebreakers in World War 2. Finally, it discusses different types of devil's advocacy and tips for its effective use, such as having multiple advocates and rotating the role to avoid negativity.