Here are 12 Horrible Histories books, which were published to coincide with the Children's BBC show in 2009. A couple of the books have creases on the covers (for an example please see the photo of the Vile Victorians book above). The books are:
Frightful First World War
Woeful Second World War
Rotten Romans
Vile Victorians
Gorgeous Georgians
Awesome Egyptians
Slimy Stuarts
Terrible Tudors
Measly Middle Ages
Vicious Vikings
Groovy Greeks
Savage Stone Age