Contemporary culture tells us the twentysomething years dont matter. Clinical psychologist Dr Meg Jay argues that this could not be further from the truth. In fact, your twenties are the most defining decade of adulthood. the Defining Decade weaves the latest science of the twentysomething years with real-life stories to show us how work, relationships, personality, social networks, identity and even the brain can change more during this decade than at any other time in adulthood. Smart, compassionate and constructive, the Defining Decade is a practical guide to making the most of the years we cannot afford to miss.