Mailbox Mania is book number 9 in the Cul-De-Sac Kids Series by Beverly Lewis. I enjoyed reading this book to my 4 and 6 year old daughters. They listened to, learned from, and like this book even though it's recommended for ages 7-10.
Beverly has done a wonderful job of weaving Christian character into a fun story line about 9 kids in 1st through 3rd grades. It's easy for kids to relate to the story, especially this one about fighting among friends. I especially like the character of Mr. Tressler who is a wise man full of compassion and kindness for the kids and helps them work through their problem. This book is a wonderful addition to your own library or a good book to borrow and enjoy with your children. It is short enough to read in an hour.