'The 2019–20 bushfires which ravaged Australia have intensified interest in Indigenous burning practices and their contribution to contemporary Australian land management. This recent interest builds upon a base established by Indigenous activism and well-circulated academic works which propose ‘Grand Unified Theories’ to explain the pre-European impact of Indigenous peoples upon environments. In this paper, I critique these theories as reliant upon binaries which either underemphasise or overemphasise impact. Just over a decade since its publication, it is timely to re-examine Bill Gammage’s The Biggest Estate on Earth and its influence upon policy and environments. Gammage’s model shares significant features with earlier popular works depicting Indigenous environmental impacts. Numerous theories incorporating ideas of overhunting have been proposed to explain the rough correlation of human arrival and the extinction of Pleistocene megafauna in Australia and North America. These Grand Unified Theories were shaped by similar tropes; they were all proposed with an eye to the present, and they have all influenced contemporary politics. I present an alternative model for conceptualising Indigenous environmental relationships that will work to advance understandings while minimising harmful repercussions and avoiding undermining Indigenous aspirations.' (Publication abstract)