I have not yet seen books titled "advanced X" that are actually grokkable, but my university courses called "introductory X" were exactly the hardest ones.
In general, laying foundations to any broad topic is hard! I imagine knowledge to be like pyramids, where the bottom support the top. But to support a tall pyramid, a large bottom is required. Thus, we get these obscenely difficult 'intro' books...
Try going to a "technical college" instead of a university. All your text books will be "advanced X". These schools have earned their reputation for being easy to pass.