The collection of articles herein focuses on the mysterious liminal region that lies between pre-symbolic and symbolic abilities. The transition between the two remains the least charted area, most intriguing of all developmental transformation in human childhood, and the least understood of all transformations in hominoid evolution. The mystery is deepened by disagreements over terminology. Simulation, imitation, pretense, symbolic play, representation, meta-representation, theory of mind, intentionality, and imagination, the very definition of these terms is contested territory. Authors of articles in this volume do not simplify the task because many of them disagree on these matters. Rather, their articles provide readers with a fascinating array of perspectives on these and related concepts. They also provide comparative data on a rich array of great ape species: humans, bonobos, chimpanzees, gorillas, and orangutans, plus some macaque monkeys.

Following in the wake of his earlier work on deception, self-awareness, and anthropomorphism, Robert Mitchell's new collection carries us further into contested twilight zones between infancy and childhood, and between other great ape and human minds. The juxtaposition between animals and children in the title is more than accidental since many of the same frameworks have been used to study and compare children of our species with those of our closest living relatives, the nonhuman great apes, an approach that has come to be known as comparative developmental evolutionary psychology (Parker, 1990).