A pair of interactive board books will provoke all kinds of conversation with a delightful and increasingly challenging series of questions related to the illustrations. Each book features three questions on every double-page spread, two of them unique to the illustration, and one repeated across the spreads. In Odd One Out: Big and Small, the repeated question is "And who is ready to go to a party?" In Odd One Out: In, Out and All Around, it's "And who is ready to go to a dance?" Each illustration features a different group of the same kind of animal. They are nearly identical, but the questions are designed to single several of them out. A page showing eight alligators asks "Who has lost all his teeth?" and "Who is long and who is short?" Young children can study the picture to find the answers. Identifying the one ready to go a party (or a dance) requires even closer observation as the clue to the repeated question is a small, black-and-white element added to the color illustrations (in this case, one of the alligators is wearing a crown). The growing challenge is due to the greater subtlety in the variations among the animals and/or the increase in the number shown on a spread (e.g., thirty almost identical hedgehogs). The final page spread shows the group of animals at the party and the dance, making it possible to go back and find those individuals in illustrations where the challenge may have been too great. Finding the answer is not always easy, but kids who love to pore over illustrations will find it a delight regardless. (Ages 2-4)