The definitive guide to keeping your brain healthy for a long and lucid life, by one of the world's leading scientists in the field of brain health and ageing. The brain is our most vital and complex organ. It controls and coordinates our actions, thoughts and interactions with the world around us. It is the source of personality, of our sense of self, and it shapes every aspect of our human experience. Yet most of us know precious little about how our brains actually work, or what we can do to optimise their performance. Whilst cognitive decline is the biggest long-term health worry for many of us, practical knowledge of how to look after our brain is thin on the ground.