You're trying to meet Al Queda, and contact A says "give this book to contact B, tell them Achmed the blind sent you." Then you pay him some $$$, or whatever is expected. Maybe there is no contact B, and you just got rooked out of your money.
Maybe there is a contact B, and you get passed along the chain, until you find yourself in an orange jump suit.
Why do you turn down a free trip home when you are already planning on going home?
ANSWER: because you still need to meet with someone to get paid before you go.
Why do you get put into an orange jumpsuit in front of a videocamera?
Perhaps because your payment is going to come in a form that you didn't expect.
Iranians and Iraqis aren't natural friends, so if there was an Iranian in Iraq who gave him the book, it was an odd situation.
I see the books as go-between messages or bonafides. You're trying to meet Al Queda, and contact A says "give this book to contact B, tell them Achmed the blind sent you." Then you pay him some $$$, or whatever is expected. Maybe there is no contact B, and you just got rooked out of your money.