Alex Bellos is a grandmaster of the puzzling world, brilliant on all things cryptic. His bestselling, award-winning books include Alex’s Adventures in Numberland, Alex Through the Looking-Glass and Can You Solve My Problems?, and have been translated into more than twenty languages. He is also the coauthor of two mathematical colouring books and the children’s series Football School. His YouTube videos have been seen by more than twenty million people, and he writes a popular puzzle blog for the Guardian. @alexbellos