Do you have books you haven't finished?

Last week, a researcher used data from Amazon to determine which books the most people had started and then not finished on their Kindles. The list of books includes mostly non-fiction, including a couple of highly discussed books from last year - Sheryl Sandberg's Lean In and Thomas Piketty's Capital in the 21st Century.  Are there books that you started but haven't finished? I know I have a few!