Indonesia's equatorial environment encourages the evolution of an exceptional number of species, each adapted to a specific habitat. To this great diversity which is common to all equatorial regions, Indonesia adds a further variation: its archipelago landform. As sea levels have risen and subsided over the past two million years, animal communities have been severed and reunited several times. Whereas Western Indonesia has, at times, formed a single landmass, Eastern Indonesia has remained a series of isolated stepping stones over which only a few mobile species, such as birds, have been able to cross. As one progresses eastward, one moves from the Asian to the Australian animal community. This transitional feature in wildlife has attracted the attention of many of the world's greatest naturalists, beginning with A.R. Wallace in the 19th century and continuing into the present. rnThe interaction between humans and animals in Indonesian history has been predictably intensive. Only now is it a main research priority to preserve the beauty and complexity of the animal communities in this huge repository of life's experiments with variation.