There is a growing recognition that the influence of residential mobility in shaping urban outcomes has been both seriously undervalued and badly understood. The Urban Institute's Metropolitan Housing and Communities Policy Center hosted an all-day symposium to begin to remedy these deficiencies. The day was devoted to the presentation and discussion of seven new papers by leading researchers in this field, with topics ranging from the varied nature of the moves that occur in low-income neighborhoods to their effects on spatial patterns and the well-being of families and neighborhoods.