When the sea-level was lower, Homo erectus walked into an extended Pleistocene land mass of mainland Southeast Asia. At no stage of the Pleistocene was this connected to the former continent of Greater Australia and there is no evidence yet for a water crossing beyond Wallace's Line, although the continuing mystery of Stegadons (elephantids) in Sulawesi, the Philippines, Timor and Flores suggests these islands were once more accessible than now. Homo sapiens entered the island chains of Wallacea to reach Greater Australia, and beyond to the Bismarck Archipelago and the Solomon Islands. When and how this happened, and what routes it took, have been matters of investigation, speculation and even simulation. This chapter reviews the main arguments.

The suggestion has long been made that the penetration of the tropical belt of this new region would have been assisted by continuity of marine and plant environments (Golson 1971; White and O'Connell 1982:51), although by New Guinea there was a change to a mainly Australian fauna, which, from a hunter's point of view, became sharply attenuated in the archipelagos farther east (Thorne 1963; Green in press).

The archaeological evidence of settlement now approaches 40,000 years. One site of that age on the Huon Peninsula of the north coast of New Guinea had access to local lagoons and fringing reefs and a forested hinterland. There were flaked, probably hafted, axes, which have been interpreted as for forest-edge manipulation (Groube et al. 1986) on this island, which by the early Holocene had evidence for early, and probably indigenous, plant domestication (Golson 1977).