Free and open source software is the default choice for the programming languages and technologies which run our world today, and it's all built and maintained by people just like you. No matter your skill level or area of expertise, with this book you will contribute to free and open source software projects. Using this practical approach you'll understand not only the mechanics of contributing, but also how doing so helps your career as well as the community. This book doesn't assume that you're a programmer, or even that you have prior experience with free and open source software. Learn what open source is, where it came from, and why it's important. Start on the right foot by mastering the structure and tools you need before you contribute. Choose the right project for you, amplifying the impact of your contribution. Submit your first contribution, whether it's code, writing, design, or community organising. Find out what to do when things don't go the way you expect. Discover how to start your own project and make it friendly and welcoming to contributors. Anyone can contribute! Make your mark today and help others while also helping yourself.