Kirk Johnson is the Sant Director of the National Museum of Natural History at the Smithsonian Institution in Washington, D.C. He is a geologist and paleobotanist known for his scientific articles, popular books, museum exhibitions, television documentaries and collaborations with artists. He is the author of Prehistoric Journey: A History of Life on Earth and Cruisin' the Fossil Freeway . Mary Ann Bonnell is the visitor services manager for Jefferson County Open Space, Colorado. For the past 30 years, Mary Ann has used art, science, and enthusiasm to connect people of all ages to the natural world. She has created scientific illustrations, cartoons, scientifically accurate costumes, and soft sculptures for wildlife refuges, botanic gardens, nature centers, museums, and aquaria.