I've started reading this after I found it on an old HN post. I went through everything except chapter 12, 13, and the latest one that just came out. I would highly recommend learning OpenGL from this tutorial if you have no prior experience with opengl or computer graphics. This tutorial dives right into shaders in the very first chapter, where as the other sources (the red book, opengl superbible) still tries to teach your fixed pipeline rendering for several chapters before introducing glsl.