Henry Handel Richardson's 1929 novel Ultima Thule, the third volume of The fortunes of Richard Mahony, portrays the final years of Mahony's failed 19th century colonial venture and the psychological challenges he faced. The novel graphically describes the onset and evolution of younger onset dementia, modelled on the author's own experiences with her father, who died of general paresis of the insane. The issues on which Richardson focuses, including Mahony's depression and suicidal despair, the difficulties of understanding behavioural change without a diagnosis, the impact of parental dementia on young children and the spouse, and the importance of person-centred care in dementia, remain relevant today.