The blueprint for our individuality lies in the 1% of DNA that differs between people. Our intellectual capacity, our introversion or extraversion, our vulnerability to mental illness, even whether we are a morning person – all of these aspects of our personality are profoundly shaped by our inherited DNA differences. In this book, Robert Plomin, a pioneer in the field of behavioural genetics, draws on a lifetime’s worth of research to make the case that DNA is the most important factor shaping who we are.