Arthur Kornhauser was an early industrial psychologist whose contributions have been neglected in written histories of applied psychology. Throughout his career, he was a staunch advocate for an industrial psychology that concentrated on improving workers' lives. This article describes his contributions to improving worker well-being in the research areas of testing, employee attitude surveying, labor unions, and mental health of workers. His most enduring quality was his outspoken advocacy for an industrial psychology that addressed workers' issues instead of management's prerogatives. On the basis of Kornhauser's accomplishments, a case can be made for him as one of industrial and organizational psychology's most important early figures.