Abstract
Jacob Levy Moreno (1889-1974) is widely considered one of the most important social scientists of the 20th century, largely for his contributions to social network analysis and psychodrama. Additionally, he was a highly regarded psychiatrist and educator whose considerable influence began in his early days in Eastern Europe and spread to the United States, which he later called home. In this entry, a brief biographical sketch of Moreno's life is provided. Then, his influence on sociometry and psychodrama is examined, and his legacy is considered.