Bill Martin Jr.

William Ivan Martin Jr. was an American educator, publishing executive, and author of more than 300 children's books including The Sounds of Mystery, Chicka Chicka Boom Boom, Brown Bear, Brown Bear, What Do You See?, Baby Bear, Baby Bear, What Do You See?, Panda Bear, Panda Bear, What Do You See?, and Polar Bear, Polar Bear, What Do You Hear?.