J. L. Gressitt New Guinea is a fantastic island, unique and fascinating. It is an area of incredible variety of geomorphology, biota, peoples, languages, history, tradi- tions and cultures. Diversity is its prime characteristic, whatever the subject of interest. To a biogeographer it is tantalizing, as well as confusing or frustrating when trying to determine the history of its biota. To an ecologist, and to all biologists, it is a happy hunting ground of endless surprises and unanswered questions. To a conservationist it is like a dream come true, a "flash-back" of a few centuries, as well as a challenge for the future. New Guinea is so special that it is hard to compare it with other islands or tropical areas. It is something apart, with its very complicated history (chapters I: 2-4, II: 1-4, III: I, VI: I, 2). It is partly old but to a great extent very young, yet extremely rich and complex. It has biota of different sources - to such a degree that it is still disputed in this volume as to what Realm it belongs to: the Paleotropical or Notogaean (Australian); or what Region: Oriental, "Oceanic," Papuan or Australian. The terms Papuasian, Indo-Australian and Australasian also have been applied to the area.