Men are more likely than women to die prematurely, and a great deal of mens excess mortality is preventable. Improving mens health and cognition is not only critical for achieving gender equality, but also for enhancing and extending mens potential to contribute to their families, the labour market and society as populations grow older. HOMME studies how mens (changing) family and working lives influence their health and cognition. Mens family and working lives are changing: Men now lag behind women with regards to tertiary education; female labour participation has increased while male labour participation has slightly decreased. Men are more apt to lose their job due to technological change. Male childlessness has risen dramatically, much more than female childlessness; in many Western countries, one out of four or almost one out of three men are now childless at age 40. Fathers are participating more in childcare, and men have partially lost their role as family breadwinners. So far, insufficient research has examined the consequences of these changes on mens health and cognition. HOMME capitalizes on the richness of Norwegian population register, survey, and genetic data to examine how mens (rapidly changing) family and working lives are related to their health and cognition across adulthood, as well as across cohorts, periods and between communities. We focus on young adulthood and midlife the life period most characterized by family transitions and work experiences. We examine cohort and period differences, mens work-face interface, the male breadwinner model and fathers participation in childcare, and disentangle selection and causality. Our data covers genes; parents, (former) spouses and partners; self-reported, clinical, and register measures of health; register data on work participation and occupation; and cognitive trajectories of N=12,000+ men between the late teens to ages 36 to 69 (and potentially beyond, pending funding of the project).