Zoo animals from polar bear to walrus make their distinctive sounds for each other, while children imitate the sounds for the zookeeper.

Bill Martin Jr, an elementary-school principal, teacher, writer, and poet, held a doctoral degree in early childhood education. His many books, among them the bestselling classics Brown Bear, Brown Bear, What Do You See?; Polar Bear, Polar Bear, What Do You Hear?; Panda Bear, Panda Bear, What Do You See?; and Chicka Chicka Boom Boom, are a testament to his ability to speak directly to children.Eric Carle was born in the United States, but spent his early years in Stuttgart, Germany. His many innovative books have earned him a place in the canon of classic children's literature. Brown Bear, Brown Bear, What Do You See? was the first book he illustrated; he then went on to write and illustrate The Very Hungry Caterpillar, The Very Busy Spider, and The Very Quiet Cricket, as well as many other books for children. Mr. Carle works in a studio near his home in western Massachusetts.www.carlemuseum.org