A discussion, with 2 tables and 3 charts, of routine medical records and their limitations and usefulness (if properly evaluated) in the investigation of industrial health. Of all medical causes of industrial absenteeism "ignorance is probably greatest about neurotic and psychosomatic illnesses..." "The methods outlined....were used to some effect in the medical supervision of operational air crews in the Royal Air Force during the last war...When all were subjected to the same external risk, breakdown rates were highest, not among pilots,...but among air gunners...not subject to the same long training as the pilot." Other examples are given of the use of such data among groups of postmen, crews of London buses and trains, etc. Informative expert discussion follows the symposium.