 Its investigative unit, devoted to studying the best practices of library loss-management, circulation and data retention, recovered 3,000 books in its first year of existence.Dewey's Library Bureau company is also said to have introduced hanging vertical files, first seen at the Columbian Exposition of 1893 in Chicago.In 1905, Dewey established the American Library Institute which was an organization conceived to provide for the investigation, study and discussion of issues within the field of library theory and practice.