This volume provides insight into gibbon diet and community ecology, the mating system and reproduction, and conservation biology, all topics which represent areas of substantial progress in understanding socio-ecological flexibility and conservation needs of the hylobatid family. This work analyzes hylobatid evolution by synthesizing recent and ongoing studies of molecular phylogeny, morphology, and cognition in a framework of gibbon and siamang evolution. With its clearly different perspective, this book is written to be read, referenced, and added to the bookshelves of scientists, librarians, and the interested public.