Welcome to the Missing Manual for Three.js

This looks like a really great resource - keen to see how it evolves!

Off topic - but does anyone know if there are any resources around about Three.js's implementation architecture? The Three.js codebase does look really nice - the code is very clear... but some of the underlying architectural ideas aren't obvious to someone who has written WebGL, but hasn't written a full 3D engine.

This is an interactive online manual for Three.js by a core collaborator on the project. The examples are interactive and easy to follow. It is still a work in progress but looks good so far.