I'm rather particular about the type of colouring book I like. They have to be colour by numbers, and be a picture where you don't know what you are colouring until you start to shade the shapes and the image appears.

I like the Colour Quest books, but whilst browsing Amazon I also found these French books, which obviously don't require translation to enjoy.

I bought the pair of Vice Versa books, where the page is a mass of swirls with one bold image you initially can see, which is a clue to the finished coloured piece you are filling in.

The publisher also has a massive range of Disney mystery colouring books, with Stars Wars, Manga and architecture filling other books.