This is one thing I've noticed a lot of people (the science majors in particular) flip out about... You just have to study, and anticipate a bit. Every lecture there is usually something that seems to pop up, whether intentional or not, over and over again. You may have not noticed at the time, but scan over your nuts and kind of reflect back. Odds are that'll be something on the exam. Even though he /she doesn't follow the book directly, you can still use it as reference. If you strive to know the material slightly better than the notes (aka not memorizing them), then you stand a better chance at an essay type question. I guess I'm used to it with the liberal arts stuff...god knows how many exams I walked into where it was just over 3 or 4 books, and 10 short stories and you'd just have to anticipate. Same with my usability courses in information science. You learn to anticipate, ask yourself "What would be a good essay question" and try to answer as many of those as you can..just by answering your own practice essays you learn the material....so try that. Kind of a roundabout way to answer the question but there you go.
