The Siwai people, now about 14,000 in number, occupy part of the dissected southern plain of Bougainville, the easternmost island of Papua New Guinea (PNG) (Figure 8.1). At the end of the 1930s the American anthropologist Douglas Oliver lived there for eighteen months and subsequently wrote A Solomon Island Society (1955). The book eventually became a classic anthropological text, both because of the detailed ethnography and the description of leadership, which provided a seminal account of a ‘bigman’ society. I first visited Siwai in 1974, similarly remaining for eighteen months, and revisited it for much shorter periods of between a week and a month in 1981, 1988 and 2001.1 There has therefore been a fragmented, though broadly continuous, analysis of Siwai society and economy over a sixty-year period, a situation that is unusual in Melanesia. Given what many have perceived as a proliferation of ethnographic and other studies in Papua New Guinea, remarkably few longitudinal studies have been undertaken there (cf. Brookfield 1973, Brown, Brookfield and Grau 1990, Gewertz and Errington 1991, Harrison 2001, Knauft 2002, Read 1986, Smith 2002) and most have limited parallels with Bougainville.