This book investigates the powerful role of online intermediaries, which connect companies with their end customers, to facilitate joint product innovation. Especially in the healthcare context, such intermediaries deploy interactive online platforms to foster co-creation between engaged healthcare consumers and innovation-seeking healthcare companies. In three empirical studies, this book outlines the key characteristics of online intermediaries in healthcare, their distinct strategies, and the remaining challenges in the field. Readers will also be introduced to the stages companies go through in adopting such co-created solutions.  As such, the work appeals for both its academic scope and practical reach.