By poking around the murky world of hoaxes, ghosts, spirit paintings, and holograms, A. Joan Saab—the vice provost of academic affairs at the University of Rochester, where she is also a professor of art history and visual and cultural studies—compiled a series of case studies that demonstrate the fascinating, and often flawed, connection between sight and knowledge. She presents her findings in a new book, Objects of Vision: Making Sense of What We See (Penn State University Press). We recently spoke with Saab about why things aren’t always as they appear, and the reasons behind the human will to believe in the unbelievable.