In this book we show how seemingly ideal boards, those with “best practice” size, composition, and structure, can still fail to provide good governance simply because they fall victim to problems inherent in all groups. While having groups of board members provide corporate oversight is probably necessary, and even advantageous in some respects, groups have a dark side too. Tendencies that occur in group behavior can destroy or obscure the talents even of highly intelligent, energetic, and well-intended individuals, causing collective blind spots, biases, and inefficiencies that can render boards ineffective. Groups often perceive risks differently from the way individual group members do and collectively fail to see problems where they really exist.