Drawing on empirical insights from the field of desktop 3D printing, this book elaborates the concept of innovation communities as a pattern of open and distributed innovation. As these communities spur a fruitful exchange of explorative, open source knowledge, they represent a novel mode of “doing innovation�, which considerably differs from established practices in market and business realms. Hence, the people that participate in these collective endeavors often develop entrepreneurial ambitions and start to exploit community-based innovations commercially. The book presents deep insights on the institutional idiosyncrasies of innovation communities, the associated dilemma of entrepreneurship and the strategies of 3D-printing startups to face the corresponding challenges.