Just a quick note to say that I have assigned _Mark Twain A to Z_ in Twain seminars (juniors,Plan II honors program, University of Texas) for two semesters, and the students have found it invaluable. The historical and biographical background enriches their understanding enormously. The plot summaries don't deter them from reading the books; they do allow them to refer to specific chapters more conveniently in our discussions, and they help everyone literally be "on the same page" in class.