This is the third book in the Young Bond series, which tell about the adventures of the young James Bond at school in the 1930s. Not that he spends much time at school - you can't when one of your masters has gone missing and the only clue is a mysterious letter. If you have ever wanted to know more about how to solve cryptic crosswords, then this book gives you a lot of information. Probably, crosswords aren't your thing. In which case, 'Double or Die' is action from beginning to end and you'll really enjoy it.
