AS THE school year opens and the youngest scurry around a school playground for the first time, the sounds are happy and the future seems good. Forget all the screeching about No Child Left Behind, because an exciting beginning for young children drowns out the pessimists and naysayers. But if the states are even going to come close to meeting the stringent requirements of that federal law, these youngest scholars must be part of the solution. This year is more optimistic than most, and a tyke's command to hurry is appropriate for what's happening in early childhood education. Illinois Gov. Rod Blagojevich stepped out in front first, winning approval from the legislature for his proposal to offer preschool programs to all 3- and 4-year-old children regardless of their family income. Oklahoma and Georgia now have universal preschools for 4-year-olds, and, despite California's rejection of a referendum on prekindergarten programs, there is a momentum among state leaders for investment in preschool, and it shows no signs of weakening. At least 43 states now have some kind of pre-K program. As a preschooler might describe these state initiatives, it's a me, too time. Policy makers have obviously read the research. The payoff from high-quality preschool experiences is significant. For those who participated in the High/Scope Foundation's Perry Preschool Project, the benefits continue four decades later in the form of more stable and productive lives than those of their peers who did not have a high-quality preschool experience. Similar results have been documented in large-scale preschool programs for many years. The Abecedarian Project, started in 1972 in Chapel Hill, N.C., was year-round and comprehensive, and it followed some poor and minority children from the age of four months through second grade. The children in the program had I.Q. scores equal to the national average by age 5; those in the extended program maintained higher-than-average reading achievement at least up to age 15. In addition, children enrolled in Chicago's Child-Parent Centers, which operate pre-K through the primary grades and are now functioning at 15 sites, have higher academic achievement and graduation rates than children not enrolled in the program. Overall, according to a review of research by the Education Commission of the States, investments in early childhood education have stronger and longer-lasting benefits than remediation or class-size reduction. At a time when policy makers are looking closely at cost/benefit ratios and federal accountability mandates, investments in preschools make sense. The word at this point in the move toward universal preschools, however, needs to be Whoa! To avoid the silver-bullet mentality that characterized the recent adoption of small schools, policy makers and educators must look deeper into the reasons that particular preschool initiatives work, and they must choose judiciously where resources should really be used. Some of the answers are as delicate as they are complicated. Just providing preschool slots for all families who want them will not ensure that young children acquire the school-readiness skills and habits that policy makers have in mind. Four more steps must be taken--three obvious ones and one that most of us dance around. First, quality has to accompany opportunity. The research is clear and straightforward about what produces positive experiences for children and what wastes money. Preschools need the same high standards as K-12 schools, including teachers trained for their work, small classes, parents as real partners, appropriate curriculum, and plenty of resources. Second, policy makers need the right kind of evaluations of preschool programs, lest they make decisions based on bad information. High-stakes tests have at best limited value with this age group. Moreover, they are difficult to implement, as shown by the current experience with evaluating Head Start on the basis of children's test scores. …