Join Ellie, a skin cell who lives on the derrière of a Boston Terrier, as she tells readers all about the amazing cells that make up every living thing on Earth. Did you know that every human is the proud owner of 37 trillion cells? (Give or take a few trillion.) They're the itty-bitty building blocks that stack together to make you, you! Join a smart and silly skin cell named Ellie as she explains what a cell looks like, what a cell does, how cells divide and multiply, and much, much more in this fascinating and funny nonfiction picture book.