More and more companies try to link their business activities with a contribution to solving big global issues such as poverty or climate change. The concept of serving the Base of the Pyramid (BoP) seeks to see the poor as a market whereby companies develop services, products and business models that are appropriate for the poor's resources and needs. One important factor for succeeding in finding new strategies to develop suitable services, products and business models for the BoP is engaging the target group itself in the innovation process. The fundamental assumption is that a bottom-up perspective in BoP ventures leads to better results for development and corporate goals, as the poor are an important link in the process. Some aspects of the bottom-up development literature have even been considered by some BoP researchers; their application, however, has not been verified. The chapter also presents an overview of the key concepts discussed in the subsequent chapters of this book.