Forge Your Future with Open Source by VM Brasseur was a book I started with incorrect expectations: I thought I was the target group, and it would explain different things from its actual content. Bummer.
But regardless: This is an excellent book for people who want to start contributing to Open Source projects and haven’t had anything to do with Open Source culture so far. It explains a bit of necessary history, and then has detailed advice on how to find a project to contribute to, set reasonable expectations, and how to actually contribute. The contents range from an explanation of licenses to how to produce a well-formed commit. I think the most helpful parts are all the scattered bits of explanations of Open Source project expectations, and the typical spectrum a newcomer will probably encounter. So if you want to get started with OS, or know somebody who does, this book should be very helpful – if you prefer learning from verbose instructions, that is. Obviously, this style is not for everybody. But if diving directly into a project with all its conventions and implicit assumptions seems too scary, this book is a good place to get started.