Empty books or blank books are novelty books whose title indicates that they treat some serious subject, but whose pages have been left intentionally blank. The joke is that "nothing" is the answer to whatever the title of the book asserts. A number of such titles have been published as attempts at satire or polemic, to some commercial success. In 2017, The Guardian commented that the trend of publishing political empty books had led to "the noble art of political parody [descending] into a one-joke turn that avoids words". Source: Wikipedia (en)