Greg Zaal has published an extensive overview of Cycles Shaders on Blender Guru.
Find Cycles Nodes a little confusing? You’re not alone.
Whilst Cycles Nodes offer almost you limitless control over a materials, many users struggle to understand it’s labyrinth of options.
Which is why this article dares to do the impossible: explain every Cycles shader in easy to understand, plain English.
Enjoy! -Greg Zaal