Caroline Walker specialises in the life and works of her great-uncle, MacDonald Gill, an architect and graphic designer best known for his comic pictorial poster maps for London Underground. Her quest to discover more about him uncovered a body of work remarkable for its quality, quantity and diversity. Her work explored his diaries, documents and other memorabilia that enabled her to piece together his colourful life story, now told in her book MacDonald Gill: Charting a Life (Unicorn 2020).