So overall I’d say it is worth reading. It is definitely on the beginner to intermediate level, which is fine. I think a total beginner to game development is better off using a library like three.js. That said, WebGL is relatively simple compared to modern desktop graphics APIs, so it’s not so crazy to write the engine from scratch. And I think if you are already well on the expert level, you probably won’t gain too much from the book. But if you are new to WebGL maybe you will learn a thing or two. I liked it.