Santa's Letter (Pop-up Book) Does Santa Claus exist? Merry Christmas, Everyone! Glittering Angel's Christmas This is a set of 4 Christmas picture books. The Santa's Letter pop-up book includes all the letters, etc. It's an exciting and fun book. The bottom two picture books have glitter applied, allowing you to enjoy beautiful, sparkling pictures. There are some irregularities when looking at the glittered areas from the back. Does Santa Claus exist? can be enjoyed by adults as well.