Place 1/4 cup of frosting in each of four bowls; tint one red, one yellow, one green and one blue. Cover and set aside. With remaining frosting, frost half of the graham crackers; top with remaining crackers. Frost the top of two sandwiches one color of frosting. Repeat with remaining colors.
Cut licorice into eight 2-1/2 inch strips. Place along one edge of each cracker (looks like book binding). Insert writing tip into decorating icing tube; pipe a title on the front of each book. Place on wire racks to dry.
Yield: 8 servings