We challenge the claim that not enough is known about the causes of health inequalities for effective action to reduce them, focusing first on the material conditions of life under neoliberalism that were described in Chaps. 3 and 4 . We provide an extensive discussion of the biology of stress, underscoring the point that psychosocial explanation of health inequalities is not ‘all in your head’. They have physiological underpinnings that are relatively well understood. This leads into a discussion of the consequences of high stress jobs that combine high demands with a low degree of control. We continue with a review of recent research on health inequalities over the lifecourse and work using the concept of the exposome: the sum total of all environmental exposures (broadly defined). We conclude with a discussion of neoliberalism and the ‘deaths of despair’ among the white US working class identified by economists Case and Deaton.