Physically Based Shading in Theory and Practice

As we all now (CG and VFX guys) Siggraph has an youtube channel called Siggraph University. A month ago they released a very very handsome presentation by Naty Hoffman called Physically Based Shading in Theory and Practice from 2015. So here it is:

Important is that it covers "only" the BRDF model (Bidirectional Reflectance Distribution Function). To see the other models jump to wikipedia.
They also released a coverage of the 2016 event with the same name. It contains 7 presentation and the first hold by Naty Hoffman again who summarize the current state of the topic.

Unfortunately some of the other presentations are not available right now because of some kind of legal issues.