Not all textbook writers are good writers. They might know their subject, but they might not know how to write.
I learned this as a college freshman when I was assigned to read a nonfiction book by an expert in his field. I read the first page and realized I didn’t have any idea what I had just read. So I reread it. Nothing. I read the page a third time and a fourth. And then I stopped.
I was a good student. The author was an expert. What was going on?
I counted the words in the sentences. Every single sentence had more than 50 words!
I analyzed the sentences. They were all complex sentences with three or four or even five dependent clauses. That meant that each sentence had at least four ideas of varying importance which I was required to juggle before I reached the period.
And every sentence had great big words—SAT kind of words.
Ph. D. or no Ph. D., that expert couldn’t write.
And so I began the time-consuming task of translating academic English into plain English which I could understand. Clause by clause, sentence by sentence, and paragraph by paragraph, I rewrote the first chapter of my text. What a pain.
From this experience, I came to believe that coherence—the ability of ideas to be understood—is the most important criteria to judge writing by. If ideas are not logical, if they cannot be understood, then they are useless.
If you are a good student and you are reading an impossible text, analyze it for its readability. Chances are, the problem is the book and not you.