Dementia is an umbrella term used to describe a group of symptoms characterised by behavioural changes, loss of cognitive and social functioning brought about by progressive neurological disorders. There are estimated to be 850,000 people living with dementia in the UK and estimates indicate that this will increase to one million people by 2025 and two million by 2051. Left undiagnosed, dementia can have an insidious and devastating impact on the outcomes for patients and their families. However, we know more about its causes and some of the factors that may increase a person’s risk of developing the condition. This paper is the first in a series relating to dementia that will follow two families through their progression with dementia and considers the recognition and initial cognitive tests that can be used in a primary care setting. Each of the papers in the series will build upon our understanding of both families, as they face different issues and scenarios over the life course of the dementia.