The birthday card Gordon sends to his grandma must travel all the way across the country in just a few days. Here we trace its route through the postal system from the time he buys a stamp and mails it until the time the letter carrier places it in Grandma’s mailbox. Obvious changes (the use of zip codes and the style of public mailboxes, for example) have been made for the U.S. edition . (Ages 4-8)