Gary Cross is Distinguished Professor of Modern History at Pennsylvania State University and author of numerous works on the history of toys and play. Among them are Kids' Stuff: Toys and the Changing World of American Childhood and Playful Crowd: Pleasure Palaces in the Twentieth Century. He is also editor-in-chief of the Encyclopedia of Recreation and Leisure in America.
David Elkind, professor of child development at Tufts University, has written and lectured widely in the United States and abroad about the cognitive and social development of children and adolescents. His numerous books include The Hurried Child; All Grown Up and No Place to Go; and, most recently, The Power of Play: How Spontaneous, Imaginative Activities Lead to Happier, Healthier Children.
Jaak Panksepp has contributed more than 300 scientific articles in the fields of psychology and affective neuroscience. As Distinguished Research Professor Emeritus of Psychology at Bowling Green State University and Baily Endowed Chair of Animal Well-Being Science at Washington State University's College of Veterinary Medicine, he is author of Affective Neuroscience: The Foundations of Human and Animal Emotions and editor of the Textbook of Biological Psychiatry.
Brian Sutton-Smith, a folklorist and educational psychologist, is among the world's foremost play theorists. His many books include A History of Children's Play: New Zealand 1840–1950; Toys and Culture, and The Ambiguity of Play. Formerly at Columbia University and now retired from the University of Pennsylvania, he is currently writing a volume on play and emotional survival.
Marjorie Taylor is professor of psychology at the University of Oregon and author of Imaginary Companions and the Children Who Create Them. She is currently conducting a multicultural study of children's pretend play. Candice M. Mottweiler, a senior psychology major at the University of Oregon, is writing an honors thesis on narrative creativity in children with imaginary companions.