Early childhood has always been the most critical developmental period of the life cycle. Yet for most of history, that essential early foundation for all subsequent learning and development was laid in the home, largely through full-time maternal care. Today, though, an unprecedented number of American mothers are in the workforce. Almost two-thirds of mothers with children under six are working outside the home, compared with fewer than one in 10 in 1940-a sevenfold increase. Nearly three in 10 mothers now return to work within two months of their baby's birth, and almost 40 percent of those with an infant under a year old are employed full time. As the American workforce--and mothers' work--has been transformed, so has early childhood. American children under five are in nonparental care for an average of 33 hours a week. Millions of children are now spending thousands of hours in paid childcare--often 10 times more hours than a year of full-day pre-K and up to 20 times more than a year of Head Start--before they enter kindergarten, meaning that childcare has a far greater impact on their development and learning. So while parents are still by far the most important influence on children's development, childcare also now plays a key role in raising young children. Improving the well-being of America's youngest, most vulnerable children is crucial to both their life chances and our nation's future. This testimony given by Katharine Stevens before the subcommittee on opportunities for state leadership of early childhood programs builds the argument that even as a growing body of science underscores the importance of early childhood, federal policy has lagged behind. Stevens maintains that current federal programs are inadequate to advance the healthy development of young children and ensure that children have a chance to start kindergarten ready to learn and succeed--giving them a fair shot at success and avoiding expensive problems down the line. She makes two key points to the subcommittee: the first on the science of early development and the second on the policy implications of that science and suggests that the science of early development strongly indicates that early childhood is a truly critical area of domestic policy--and, in the long run, may be the most important area of education policy. Stevens further argues that the federal government has a crucial role in advancing better early care and education, especially for the most vulnerable children. Because it is such a critical area, though, Stevens believes the most important federal role now is to promote state leadership. She calls for new ways to be found to promote and leverage growing state commitment to early childhood, to incentivize state innovation, and to highlight strategies and activities of currently leading states, particularly around supporting lower-income families by improving access to high-quality childcare.