For the fifth time ever, best friends Elephant and Piggie have five BIGGIE adventures in one book! From award-winning, best-selling author and illustrator Mo Willems, this BIGGIE bind-up of Elephant & Piggie adventures will make readers want to celebrate! This bind-up includes the titles: I Am Invited to a Party! , I Will Surprise My Friend! , Happy Pig Day! , Waiting Is Not Easy! , and The Thank You Book .