My father and I just finished Murder on the Orient Express by Agatha Christie, easily and justly one of her most famous novels.
We knew the book's reputation when we began. What we did not know was that by the end we would be declaring Christie an unquestionable equal to the Lady of Endless Surprises herself, the great Diana Wynne Jones. Not many authors can make us bang our heads against the wall with shock after total shock, but Agatha Christie just did. Truly she is the worthy heir to Sir Arthur Conan Doyle, for Sherlock Holmes himself could not have done better this day than M. Hercule Poirot.
(Yes, yes, I know this is not a fantasy novel. But any book that we declare an equal to the best of Diana Wynne Jones deserves attention here.)