“Software is eating the world” [1] - The famous quote and article by Marc Andreesen, founder of Netscape, is now 12 years old and it is fair to say: He was right, software is the driver of modern economy and pervasive throughout all industries. Taking it one step further, we argue that while software has eaten the world, open source is eating software. Open source makes up 80% - 90% of applications and if we think about it, it is clear that the modern IT industry would not be where it is today without open source. Just to name one example, the internet as we know it is based on open source technology. This lecture will give an introduction to open source and will try to investigate how open source can be applied successfully - in industry and research alike. We will cover aspects such as licenses, governance, best practices, success stories and the role of open source foundations. Last but not least we will have a look at how we can increase the impact of research projects with open source. [1] https://a16z.com/why-software-is-eating-the-world/