The sad fact is that a lot of us have to give quizzes on plots to
encourage the students actually to read the books in the first place. I
generally do that on the first day of discussion of the book, and it
makes a big difference. I used to wonder if I wasn't an inspiring enough
teacher, and that's why students showed up in my classes without reading
the books. But I've become convinced that I'm not the problem. I try to
deemphasize the punitive edge of quizzes is by telling students that
they're getting credit for something they would be doing anyway.
    As for plot summaries in books and elsewhere, it doesn't take much
to come up with an objective quiz that the average plot summary won't
cover very well. Besides, the student who tries a quick once-over of a
plot summary is probably not going to remember much it anyway. This is
the same principle that more or less guarantees that a paper written
from Cliffs Notes is going to be a lousy paper.
    Interestingly enough, with Huckleberry Finn, at least, I find that
students frequently slough off reading it in a college class because
they already read it in high school and assume that once is enough. (I
think high school--and college--teachers sometimes encourage this notion
by laying on to students nicely shaped potted summaries of what works of
literature "really mean ".) So I'm pleased to offer whatever incentive I
can for the pleasure of re-reading Huckleberry Finn, or any good book,
for the second, or third, time.

GJ