There is a clear trend in rich countries that despite rising incomes and living standards, the gap between rich and poor is widening. What does this mean for our health? Does increasing income inequality affect outcomes such as obesity, life expectancy and subjective well-being? Are rich and poor groups affected in the same ways? This book reviews the latest research on the relationship between inequality and health. It provides the reader with a pedagogical introduction to the tools and knowledge required to understand and assess the issue. Main conclusions from the literature are then summarized and discussed critically.