The broad array of data we present each year in the "KIDS COUNT Data Book" is intended to illuminate the status of America's children and to assess trends in their well-being. By updating the assessment every year, KIDS COUNT provides ongoing benchmarks that can be used to see how states have advanced or regressed over time. Readers can also use KIDS COUNT to compare the status of children in their state with those in other states across several dimensions of child well-being. The 10 indicators used to rank states reflect a developmental perspective on childhood and underscore our goal to build a world where pregnant women and newborns thrive; infants and young children receive the support they need to enter school prepared to learn; children succeed in school; adolescents choose healthy behaviors; and young people experience a successful transition into adulthood. In all of these stages of development, young people need the economic and social assistance provided by a strong family and a supportive community. As the "KIDS COUNT Data Book" has developed over time, some of the indicators used to rank states have changed because weaker measures have been replaced with stronger ones. Consequently, comparing rankings in the 2008 "Data Book" to rankings in past "Data Books" does not always provide a perfect assessment of change over time. However, Appendix 2 shows how states would have ranked in past years if the same 10 measures used in the 2008 Data Book had been employed. The table in Appendix 2 is the best way to assess state changes over time in overall child well-being. Contents of this "Data Book" include: (1) "A Road Map for Juvenile Justice Reform" essay; (2) Summary and Findings; (3) Child Well-Being in Puerto Rico; (4) National Indicator Maps: State Rates; (5) Profiles; (6) United States Profile; and (7) Profiles in alphabetical order for 50 states and the District of Columbia. Also included are: Definitions and Data Sources; Criteria for Selecting KIDS COUNT Indicators; Primary Contacts for State KIDS COUNT Projects; and About the Annie E. Casey Foundation and KIDS COUNT. Appended are: (1) Multi-Year State Trend Data for KIDS COUNT Key Indicators; and (2) Multi-Year State Trend Data for Overall Ranks. (Contains 3 tables and 82 endnotes.) [For "KIDS COUNT Data Book, 2007," see ED497926.]