If you find an error in the book, please email me about it. If you are the first to find a mistake, I will mail you a very pretty piece of paper containing the private key to 1 Bitcoin.
In Chapter 15, "Cleverness When It Counts", Basil tries to convince Anton that zero is odd. Zero is most definitely even, but I wanted him to to try to argue the other side. Most of what Basil says is just an attempt to muddy the waters, but one sentence is actually wrong. He says: "Now see here, Anton: any odd number multiplied by itself is even, and every even number multiplied by itself is also even. So multiplication doesn't prove it either..."
This is completely wrong. I'd like to be able to say that it was a trap for the unwary, but it was a genuine mistake. An odd number times and odd number will always be odd, not even. Slawek Biel of London and Alexandra Adams, a teacher in Alberta, spotted it independently.