In fairness to Stewart, his calculus book is actually pretty awesome. I had a class that used another book, written by one of the professors, and went out and bought another copy of Stewart's book because I could actually follow it. He does a very good job of explaining something that can be difficult. Trying to learn from a poorly constructed book really increased my respect for the quality of Stewart's explanations. There is a very good reason that his book is so well used.