The Missing Piece is a children's picture book by poet Shel Silverstein.

The story centers on a circular shape-like creature that is missing a wedge-shaped piece of itself.

But after the circle finally finds the exact-sized wedge that fits it, it begins to realize that it can no longer do the things it used to enjoy doing, like singing or rolling slowly enough to enjoy the company of a worm or butterfly.

So it gently puts the piece down, and continues searching happily.

A sequel was published in 1981 entitled The Missing Piece Meets the Big O, which is told from a Missing Piece's point of view.