Further Reading

This guide focuses on history, context, and lessons learned—the "why" behind licensing decisions and what happened when things went wrong. It's one perspective among many.

If you need something different, here are resources worth your time.

Quick Reference Tools

When you just need to pick a license or check what one requires:

• choosealicense.com — GitHub's license picker. Answer a few questions, get a recommendation. Good starting point for new projects.

• tldrlegal.com — Plain-English summaries of what licenses allow, require, and forbid. Useful for quick compatibility checks.

• SPDX License List — The canonical list of license identifiers. If you're adding license metadata to code, this is the reference.

Other Guides

These cover similar ground with different approaches:

• A Dev's Guide to Open Source Software Licensing — GitHub's ReadME Project guide. Solid fundamentals, well-organized reference material.

• Open Source Licenses Explained — It's FOSS coverage of the major licenses. Good for quick comparisons.

• Open Source License Best Practices — Linux Foundation's compliance-focused guide. Covers SPDX identifiers, SBOMs, and enterprise governance topics this guide doesn't address in depth. (I cover SBOMs and supply chain security in my software building guide.)

Books

For deeper exploration of the history and philosophy:

• Fogel, Karl. Producing Open Source Software. Available free at producingoss.com. The practical guide to running open source projects. Less about licensing specifically, more about everything around it.

• Moody, Glyn. Rebel Code: Linux and the Open Source Revolution (2001). The history of Linux and the movement around it. Excellent narrative if you want the full story.

• Raymond, Eric S. The Cathedral and the Bazaar (1999). The essay that shaped how people talked about open source development. Dated in some ways, historically important.

• Weber, Steven. The Success of Open Source (2004). Academic analysis of why open source works as a model. Denser than the others, more theoretical.

Official Sources

When you need authoritative interpretations:

• FSF License List — The Free Software Foundation's commentary on licenses. Opinionated but thorough.

• OSI Approved Licenses — The Open Source Initiative's list of licenses meeting their definition.

• Apache Legal FAQ — How the Apache Software Foundation handles licensing questions. Useful if you're working with Apache-licensed code.

What This Guide Does Differently

Most licensing guides answer "what does this license require?" This guide tries to answer "what happens when licensing decisions meet reality?"

The Lessons Learned section is the heart of that approach—case studies of forks, lawsuits, and corporate pivots that shaped how the community thinks about licensing today.

If you want a quick reference, the tools above are better. If you want to understand why people get passionate about license compatibility or why "source available" triggers such strong reactions, that's what this guide is for.