One of my favorite books to introduce small children to family history is Climb the Family Tree, Jesse Bear! written by Nancy White Carlstrom and illustrated by Bruce Degen. This is the same team that has created all of the Jesse Bear books, including Jesse Bear, What Will You Wear? Also, the illustrator wrote and illustrated the popular Jamberry. Climb the Family Tree, Jesse Bear is aimed at children from age two to six, and even the youngest children can enjoy its pictures and rhymes.
The book describes Jesse Bear attending a family reunion. He interacts with various family members, from cousins to great-aunts. He listens to family stories and engages in various family traditions. There is a colorful family tree at the start of the book and pictures of all of the family members on the back cover. These can be tools to learn about organizing and displaying family relationships. But most importantly, it is fun, which will engage children and bring them back to this book about family again and again.