This essay shows that the adoption of intelligence tests by the schools was a complex development. Tests were adopted during the 1920s as part of the reform program fashioned by the network of applied psychologists and school people. While the network itself often viewed testing as a means to improve the schools and society, immigrants and blacks did not share their vision. The adoption of the tests proceeded quickly for several reasons: (1) the need for an efficient means of sorting students; (2) the catalyst of World War I; and (3) the consensus among school people that the use of tests promoted a more efficient and scientific education. In the last two decades the progressive reform of intelligence testing and ability grouping has come under sharp attack. Revisionist historians and social activists have criticized intelligence tests as racially biased, elitist, and as obstacles to social equality. Historically it cannot be denied that the rhetoric and the programs of progressive reformers occasionally led to inequality in the schools. Yet as the nation seeks to reevaluate policy regarding the use of tests, it is essential to consider the origins of intelligence testing in the progressive era. (RL)