At the outset, Head Start was hailed as a solution to the cycle of poverty. Politically expedient--who would oppose aid to poor three-year-olds?--it began as an eight-week summer session and quickly expanded into a full-year program. Almost immediately, skeptics challenged its oversized expectations; then neighborhood radicals challenged its conventional administration; and even before the dust settled, a Westinghouse Learning Corp. report found Head Start ineffective in improving cognitive abilities--higher test scores faded by third grade. Today it survives but remains something of a problem child, its potential unrealized. Zigler and Valentine's ambitious review covers Head Start's checkered history, gathers in the reminiscences and more formal writings of its policy makers and participants, and concludes with a strong argument for its preservation. Head Start was intended, they remind us, not to raise IQ points but to give ""deprived"" children the opportunity to acquire social competencies; emotional and motivational development were equally valued components of the original plan, along with medical and dental screening and improved nutrition. And parent involvement was a cornerstone: parents received childcare training and were encouraged to assert themselves at Head Start centers and in their communities. Given these goals, now somewhat eclipsed, Head Start has had a measure of success; and when those Westinghouse statistics are re-examined and re-interpreted, they no longer seem so significant. (It's just as likely that poor schools fail to maintain Head Start gains.) The editors have collected a wide range of writings to illuminate ongoing dilemmas--how regular assessments rarely lead to policy reformulations, how staff turnovers at all levels compromise effectiveness, how in many centers adults prosper more than children. (And they include agreeable incidentals: the Havasupai tribe in the Grand Canyon receives their materials via pack animals and helicopters.) The vexing issue of quality control remains, but the value of early intervention with support at home and continuity at school becomes difficult to dispute.