Caroline Macdonald (1874-1931) was a Canadian who spent almost her entire working life in Japan, performing a significant role there both in the establishment of the YWCA and in prison reform. A native of Wingham, Ontario, Macdonald graduated from the University of Toronto in 1901 in mathematics and physics and later moved to Tokyo to work for the YWCA. Her subsequent career in social work made her the best-known foreign woman in Tokyo during the 1920s.

In A Heart at Leisure from Itself, Margaret follows Caroline Macdonald's life and career, focusing primarily on her work in Japan on behalf of incarcerated criminals. She also established a social settlement, Shinrinkan - the Home of the Friendless Stranger - and was a mentor of labour union leaders and social democratic politicians.

Macdonald was involved with feminists and feminist causes of her time and played a part in the slowly changing position of Japanese women, always with a moderation that did not necessarily reflect her own strongly held opinions. To a degree unusual among foreigners, Macdonald identified with the lives and aspirations of her Japanese friends and their country. Her story becomes partly their story.