Ida Greaves, who was born in Barbados in 1907, is one of the "missing female voices" of early development economics. This biography, the first for Ida Greaves, attempts to construct her career and era before the past wholly disappears. The biography covers her early years in Barbados, her time at boarding school in England, at McGill University in Canada where she focused on human behaviour under the influence of changing social and political histories and also published an early path-breaking study of black migrants into Canada, and her later research at Harvard and Columbia in the United States and at the London School of Economics. Individual chapters follow her career acting as economic adviser to the Colonial Office in London, where she worked alongside Arthur Lewis, and at the fledgling United Nations in New York. She published in top journals and produced an outstanding study of the influence of colonial monetary systems on poor countries. This accessible biography provides unexpected insights into personalities and institutions during a critical period in late colonial history. The issues it raises of class and race, gender and inequality, poverty and unemployment, are of no less relevance today than they were in her lifetime.