This release has lots of new material, fixes, and updates across the three books in this series. All three books are online and free, with accompanying code available from GitHub. Enjoy!
Most of the changes are in the v4.0.0-alpha.1 and v4.0.0-alpha.2 releases.
Oh yea? Well I'm planning on making "Ray Tracing in _One Afternoon_" and I'm going to not only make it public domain, I'm going to personally deliver a printed copy to everyone in the world.
(RTOW is lovely. I love how it has evolved. Thank you!)
(https://github.com/chunky/sqlraytracer was the one I created. Slightly obtuse but I really enjoyed writing it)