I will partially disagree with Norm on the topic of re-reading. I imagine that he most likely disagrees with himself on this question: re-reading 'books' as in the story he links to becomes re-reading 'novels.' But I would imagine that in his professional capacity he re-reads all the time. At the very least his research strongly gives off this impression.
This is, I think, an important point pedagogically and otherwise. Students can rarely be bothered to read something assigned to them once, and it usually comes as a shock to them that I believe a first reading is close to functionally useless. For any serious reflection, how can it possibly be of use, given that you don't know where the argument, narrative, etc is going? Second and third readings begin to allow you to see and judge the overall structure of a work, and begin to understand the decisions that go into placing one piece into the whole. The same thing applies, I think, to those very best of novels: a good, big, important work is going to require more thinking and piecing together than a single reading could ever provide; but if the work is worth it, that effort is repaid.