Mary Montgomerie Bennett (1881-1961) is an important but under-recognised figure in Australian history. A member of a successful squatting family, she became a voice for reform at a time when Aboriginal Australians had their citizens' rights curtailed by repressive state laws. From her late forties until her death she fought for justice on behalf of the first Australians. She was a teacher, a writer and an advocate. She vehemently opposed the separating, on racial grounds, of Aboriginal children from their families. She put the case, decades before campaigns began, for Aboriginal rights to traditional lands. And she argued for citizenship rights, including equal pay and access to old age pensions, for Aboriginal people. A friend described her as 'a white hot flame', relentless in pursuit of a better world for the people she loved. This first comprehensive biography seeks the sources of Mary's inspiring energy, maintained throughout her life, in her family background and early life experiences.