I have some background in rendering, but most of it is older, i.e. things like PolyRay and POV-Ray from 10-20 years ago - so pretty much all direct illumination / eye-based. I have a little Blender experience, but not much with its renderers, whether Cycles or BI. I get how path tracers work, but have almost no experience in them.
I’m routinely lost when looking around at all the things I have control over in Appleseed, but both docs and tutorials are a bit scarce. Now, I know that most of this wasn’t invented from scratch in Appleseed, so I’m sure that most of it I can read about somewhere. What is a good place to get some background and some practical explanation on things like renderer settings and, particularly, with different materials and their parameters and interactions? Is something like PBRT a good place to start?