Open source has grown outside the boundaries of hackers, amateurs and software developers, creating a humongous potential in many different areas and aspects of society. The intrinsic and extrinsic motivations that drive open source have been in the subject of much research, but how they affect each other when paid and unpaid contributors come together is still hidden in obscurity. In this book I investigate how intrinsic and extrinsic motivation correlate with each other and how those correlations affect paid and unpaid open source software contributors. If you are working with open source developers as a target group, this book may help you map the preferences of your target group and create more accurate personas. The content of this book might also be of interest if you would like to learn more about how the participants of open source developments are thinking.