Where to find a good introduction to GLSL compute shaders?

I’d trying to learn how to create computer shaders. I’ve found a bunch of tutorials online and think I’m getting the hang of it, but it would be nice to have something more comprehensive, like the OpenGL orange book. (For example, how do I decide what sizes of workgroups would be best?)

Is there any good introduction for compute shaders for someone already familiar with writing traditional vertex and fragment shaders?