The mental health of people at work, whether manager or bench worker in a factory, doctor or nurse in a hospital or surgery, executive or clerk in an office, is obviously of great social and even national importance. In most years far more days work are cost from psychiatric illness than from strikes; and, besides, there is considerable loss of efficiency from illness, even when the worker does not go absent. Although the majority of illnesses are probably due to a concatenation of factors, including domestic, there are some conditions in factories and elsewhere that appear to precipitate or predispose to mental ill-health.