Inequality in family wealth is high, yet we know little about how much and how wealth inequality is maintained across generations. We argue that a long-term perspective reflective of wealth's cumulative nature is crucial to understand the extent and channels of wealth reproduction across generations. Using data from the Panel Study of Income Dynamics that span nearly half a century, we show that a one-decile increase in parents' wealth position is associated with an increase of about four percentiles in their offspring's wealth position in adulthood. We show that grandparental wealth is a unique predictor of grandchildren's wealth, above and beyond the role of parental wealth, suggesting that a focus on only parent-child dyads understates the importance of family wealth lineages. Second, considering five channels of wealth transmission-gifts and bequests, education, marriage, homeownership, and business ownership-we find that most of the advantages arising from family wealth begin much earlier in the life course than the common focus on bequests implies, even when we consider the wealth of grandparents. We also document the stark disadvantage of African American households in terms of not only their wealth attainment but also their intergenerational wealth mobility compared to whites.