Recommended.

For two or three years I've noticed this book. In the library and in bookshops.
However, I didn't on those occasions go any further, such as borrowing or buying it.

While in Te Anau last week I did buy it and with feet up, found myself intrigued. Inventively put together as if has been written by an autistic boy, Christopher. Christopher works on mathematical puzzles in his head as a way of relaxing. Fixated with the dangers of making assumptions, he recounts this joke:

There are three men on a train. One of them is an economist and one of them is a logician and one of them is a mathematician. And they have just crossed the border into Scotland (I don't know why they are going to Scotland) and they see a brown cow standing in a field from the window of the train (and the cow is standing parallel to the train).
And the economist says, 'Look, the cows in Scotland are brown.'
And the logician says, 'No. There are cows in Scotland of which one, at least one is brown.'
And the mathematician says, 'No. There is at least one cow in Scotland, of which one side appears to be brown'.