This book describes one of our closest relatives, the orangutan, and the only extant great ape in Asia. It is increasingly clear that orangutan populations show extensive variation in behavioral ecology, morphology, life history, and genes. Indeed, on the strength of the latest genetic and morphological evidence, it has been proposed that orangutans actually constitute two species which diverged more than a million years ago - one on the island of Sumatra the other on Borneo, with the latter comprising three subspecies. This book has two main aims. The first is to carefully compare data from every orangutan research site, examining the differences and similarities between orangutan species, subspecies and populations. The second is to develop a theoretical framework in which these differences and similarities can be explained. To achieve these goals the editors have assembled the world's leading orangutan experts to rigorously synthesize and compare the data, quantify the similarities or differences, and seek to explain them. Orangutans is the first synthesis of orangutan biology to adopt this novel, comparative approach. It analyses and compares the latest data, developing a theoretical framework to explain morphological, life history, and behavioral variation. Intriguingly, not all behavioral differences can be attributed to ecological variation between and within the two islands; relative rates of social learning also appear to have been influential. The book also emphasizes the crucial impact of human settlement on orangutans and looks ahead to the future prospects for the survival of critically endangered natural populations.

Serge Wich received his MSc in animal behaviour in 1995 at Utrecht University (the Netherlands) for which he conducted a study on food competition in wild Sumatran orangutans. In 2002, he received his PhD from the same university for a study on the structure and function of male Thomas langur long-distance vocalizations. In 2003, he started as a post-doc at Utrecht University to study 'cultural behaviour' of orangutans in two orangutan poplulations, one on Sumatra and the other on Borneo. Currently, he is a visiting scientist at Great Ape Trust of Iowa from where he continues with field work on Sumatran orangutans and is also involved in studies on the orangutans and bonobos at Great Ape Trust.
Suci Utami Atmoko started conducting research on orangutans while at the Universitas Nasional in Jakarta where she received her BA for a study on female reproduction. She continued her orangutan research on male bimaturism research at Utrecht University where she obtained her PhD in 2000. Since then she has been involved in orangutan research and conservation activities in Borneo and Sumatra. She is currently a lecturer at Univeritas nasional (jakarta, Indonesia).
Tatang Mitra Setia started studying Indonesian primates in 1979 at the Ketambe research site. In 1988 he began his studies on social relationships of orangutans. In 1995 he received a MSc at Universitas Indonesia (Jakarta, Indonesia). He is involved in orangutan research on both Borneo and Sumatra and currently he is the Dean of the Biology Faculty of Universitas Nasional (Jakrta, Indonesia).
Carel van Schaik has studied primates in Indonesia and elsewhere since 1976. He received his MSc at Utrecht University (the Netherlands) for a study on behavioral ontogeny in orangutans. In 1985 he obtained his PhD at the same unviersity for a study on the socioecology of long-tailed macaques. After a post-doc at Princeton University, he worked as a lectured at Utrecht University and later as a Professor at Duke University. He is interested in the social evolution of primates and currently studies orangutans at two sites in Indonesia. He is the author of a large number of scientific articles and has edited several books on topics ranging from male infanticide to primate conservaton. Currently he is professor and the director of the Antropological Institute & Museum of the University of Zurich, Switzerland.