There are almost a million people in the UK living with dementia, and Alzheimer’s is the most common form. But the disease actually starts long before any noticeable symptoms appear, and over the past decade, studies have shown that it is much more complex than previously thought. Julie Williams has been at the forefront of this effort, uncovering the genes that make us susceptible, and has transformed our understanding of this devastating disease. She has brought researchers together to create bigger datasets and more powerful studies. Her current work with scientists from other fields, like immunology and computational biology, is looking at the mechanisms underlying Alzheimer’s disease. Julie tells Jim about her early interest in science, her time as Chief Scientific Advisor to the Welsh government, and her belief in ‘team science’ – collaborating and sharing research findings across international borders and disciplines. Produced by Florian Bohr