Making Cents by Elizabeth Keeler Robinson is a great introduction to money. This would be very useful in a unit to teach about currency and what each coin/dollar represents. I was fascinated with how the author shows that a dime, for instance, is worth ten penny nails, two wood screws or a marking pencil. I'd never have thought of a dime that way!! Bob McMahon's illustrations are very fun and add to the interest in this one. What a fun book! Definately worth a look!