This chapter has only been an introduction to free software licensing, trademark, and patent issues. Although I hope it contains enough information to get you started on your own open source project, any serious investigation of legal issues will quickly exhaust what this book can provide. Here are some other resources:
The OSI license introduction page is a well-maintained source of information about widely used open source licenses, and offers answers to frequently asked questions. It's a good place to start if you have a general idea of what open source licenses do, but now need more information, for example to choose a license for your project.
Open (Source) for Business: A Practical Guide to Open Source Software Licensing by Heather Meeker. Published April 2015. https://www.amazon.com/Open-Source-Business-Practical-Licensing/dp/1511617772
Although organized around licensing and open source legal concepts, this is a general guide to open source and business, and the author has a lot of experience in the field.
Intellectual Property and Open Source: A Practical Guide to Protecting Code by Van Lindberg. Published by O'Reilly Media, first edition July 2008, ISBN: 978-0-596-51796-0
This is a full-length book on open source licensing, trademarks, patents, contracting, and more. It goes into much deeper detail than I could in this chapter. http://shop.oreilly.com/product/9780596517960.do for details.
Make Your Open Source Software GPL-Compatible. Or Else. by Dr. David A. Wheeler, at http://www.dwheeler.com/essays/gpl-compatible.html.
This is a detailed and well-written article on why it is important to use a GPL-compatible license even if you don't use the GPL itself. The article also touches on many other licensing questions, and has a high density of excellent links.