Today''s markets are widely exchangeable and consumers start challenging brands on their proclaimed brand promises. Consumers have become more critical to the extent that they start dictating what, where, and when they want to consume products and services. They even create new ways of consumer resistance, like so-called anti-brand communities. This allows space for new brand positioning strategies, which might not have come from a self-defined branding approach. It is much more about a brand being perceived as authentic, credible and real. Even if the term ‘authentic'' is mentioned quite frequently and seems to be a new source of competitive advantage, it has not been sufficiently specified, yet. This book aims to contribute to the currently existing marketing literature, by developing a theoretical concept of brand authenticity. It will show why authenticity is that fundamental for brands, and why authenticity has gained momentum. Furthermore, it will explain relevant criteria for sustainable branding as well as discuss how to build and maintain an authentic brand.