A distillation of forty years of research and medical experience, 'The Right Life' sets out a new theory of human thriving. Tracing our development as individuals from the beginnings of evolution to the twenty-first century, he sets out his own theory, the 'Fit Principle', which proposes that every human strives to live in harmony with their fellow humans and their environment. Rather than a ceaseless quest for self-improvement and growth, he argues, our collective goals should be individual self-acceptance, as we embrace the unique matrix of skills, needs and limitations that makes each of us who we are.