Interpreting involves the oral translation of oral discourse and interpreters have played important roles throughout history, including in business and conferences. Research on conference interpreting has gone through experimental, practitioner, and renewal periods, with early writings in Geneva in the 1950s and the first manual published in 1952. A key development was the establishment of training programs like ESIT in Paris, which adopted the theory of sense, though this theory was later questioned by a new generation beginning in the mid-1980s.