Sean Callery is an author and primary-school teacher. He has written several information books for publishers such as HarperCollins and Which?, including titles about codes and ciphers, children's party games and famous dictators. Clive Gifford has written more than 100 information books for children on a wide range of subjects. For Kingfisher, Clive's titles include The Kingfisher Football Encyclopedia, Olympics, Kingfisher Knowledge Spies and The Kingfisher Book of Living Worlds. Dr Mike Goldsmith studied the philosophy of time and space at Keele University, where he also obtained his PhD in astrophysics. Formerly the head of Acoustics at the UK's National Physical Laboratory, he has written many non-fiction books for children.