It doesn’t take a genius to recognize that James Joyce’s novel Ulysses is a work of genius—but it might take one to truly understand it. According to a new survey, it’s one of the top 10 most confusing books of all time. Researchers at UK-based online retailer OnBuy.com asked 3205 people to dish on which books puzzled them the most, and compiled a list based on the 10 most common responses. To rank those titles from most to least confusing, they relied on monthly search volume data from Google. Plot summaries were a trend across the board, and people are also especially interested in ending explanations and overarching meanings.