This paper examines the dynamics of poverty. Previous analyses of dynamics of poverty have either examined only fluctuations in the male head of family's earnings or looked at the frequency of poverty periods over a fixed time frame. A more appropriate way to understand the dynamics of poverty is to define spells of poverty. Using this methodology, it can be seen that although many people have very short spells of poverty, the few with very long spells account for the bulk of all poverty and represent the bulk of the poor at any point in time. Spell methodology also allows an estimate of the extent to which poverty spell beginnings and endings are associated with changes in income or changes in family structure. Less than 40 percent of poverty spell beginnings seem to be caused by a drop in the head's earnings, while 60 percent of endings occur when the head's earnings increase. Thus, to understand the causes and potential remedies for poverty, researchers must focus on household formation decisions and on the behavior of so-called secondary family members. (Author/KH)