What was the most difficult book to read?

There was no definite answer to this question because everyone might have a different definition of the most difficult book to read. Some people might think that classic literary works such as Dream of the Red Chamber and Outlaws of the Marsh are the most difficult to read because they have complicated plots, profound character analysis, and complicated language structures. Others might think that science fiction, horror novels, or psychology books are the hardest to read because these topics often require a certain amount of scientific knowledge and background knowledge. In addition, the most difficult books did not necessarily mean that these books were worthless. Sometimes, they might give readers a new way of thinking and worldview. Therefore, choosing the most difficult book should be a personal decision. The reader should choose according to his own interest and reading level.