Puzzles for Spies

Oh the treasures one can find in the local bookshop! And this year, I am really developing an interest for all things spies. Anyway, during my last stop at the local bookshop, I saw Puzzles for Spies. I did not buy it, although I was very tempted. Not for me, of course not, but for my son, who loves these kinds of games. It's produced by the GCHQ, so it must have at least some level of authenticity. Be that as it may, it can also inspire us in our games. So I might buy the book for his birthday.