A lonely missing piece sits all by itself, waiting patiently for someone to come along and take it somewhere. It dreams of finding the perfect shape to fit into so it can finally roll and see the world. As time passes, it meets all sorts of different ones. Some fit perfectly but cannot roll, while others can roll but do not fit at all. Just when the missing piece thinks it might be stuck forever, it meets the Big O, a shape that teaches it a wonderful and surprising secret about moving forward. Shel Silverstein uses simple, beautiful drawings and gentle words to tell a powerful story about independence, friendship, and discovering your own strength. This touching fable shows that you do not always need someone else to carry you along. Sometimes, you just need to figure out how to build your own momentum and roll all by yourself!