The first article in this series traces the initial development of the concept of evaluation use. As a field, evaluation has always paid attention to the potential for use, both in decision-making and in changing people's thinking. The broad history of the field as we know it today stemmed from two streams: one focused on tests and measurement, primarily in education, and a second focused on social research methods, primarily concerning knowledge utilization. Evaluation use had its roots in both streams, resulting in three broad categories for discussing the use of evaluation findings: instrumental use, conceptual use or enlightenment, and symbolic use. The additional category of process use, added years later, highlighted the potential utility of people's participation in the evaluation process.