This book teaches pre-schoolers how to describe size simply by having them ask the question `Who's the biggest?' to the pair of objects on every spread. The fun is in the reply; using evocative verbs, the book helps to conjure up some of the character of the object speaking: `"I am!" trumpets the elephant', or "I am!" warns the hammer to the nail. Parents and guardians reading the book to toddlers will inevitably be drawn into the game, and will enjoy making their replies as expressive as possible. The skills being taught are basic mathematics, which Chedru turns into a fun and creative game that children will love playing. By requiring the reader to actively ask the question `Who's the biggest?' on every page, the book enourages children to apply an enquiring mindset to the things they encounter.