This work focuses on the themes of old age, ageing and dementia. It seeks to explore how people who are caring for a loved one with dementia construct their ideas about the illness and how their experience of caring translates into their ideas about old age and ageing. These themes are discussed against the background of the third age, active ageing and the social imagination of the fourth age as conceived by Gilleard and Higgs. The thesis shows how the respondents form their ideas about their own old age in the context of third age culture, what aspects of old age they consider most important, and conversely what constitutes for them an image of a bad old age. At the same time, this thesis captures the respondents' experience of caring for their parent and how they construct ideas about this illness on the basis of this experience. The specific aspects of the disease of dementia are discussed in the context of key elements of the social imaginary of the fourth age and its most debated concepts, including the concept of personhood. The problematic aspects of the disease are reflected in the experience of caring for a loved one with dementia, and reflected in the fear of the disease in terms of their impact on the relationship with the parent, the nature and need for care.