This Friday my special guest will be Professor Kathryn Edin author of  "Why Poor Women Put Motherhood Before Marriage". A landmark study identifying the causes of urban family breakdown.    Kathryn Edin is a Professor of Public Policy management at the Harvard Kennedy School. Her research focuses on urban poverty and family life, social welfare, housing, child support, and non-marital childbearing. Her fourth coming book with Timothy J. Nelson, Doing the Best I Can: Fatherhood in the City(2013), is a multi-year ethnographic study of 110 black and white low income unmarried fathers in inner-city Philadelphia and Camden, NJ. Previous books include Promises I Can Keep: Why Poor Women Put Motherhood Before Marriage(2005, with Maria J. Kefalas), the results of an ethnographic study of 165 black, white, and Puerto Rican low-income single mothers, also drawn from poor neighborhoods in Philadelphia and Camden: Unmarried Couple with Children(2007, with Paula England), an analysis of a four-year study of 48 unmarried couple who shared a birth in 2000; and Making Ends Meet: How Low Income Single Mothers Survive Welfare and Low Wage Work (1997, with Laura Lein), a four-city study of low income single mothers' economic survival strategies.