This paper, by a general practitioner and a psychiatric social worker, is based upon an investigation, at present in progress, into the influence of the family upon children's achievement and emotional adjustment, which is supported by the Mental Health Research Fund and supervised by Dr. D. A. Pond. In the present paper we are reporting on some of the data collected from part of the population being investigated. The main survey will include all families registered with the general practitioner (A.R.) where the head of the household is in Social Class III, IV or V, in which there are children born between 1949 and 1954, and from which at least one parent is also registered. From the first 70 families visited in this survey 50 couples, including those who cohabit but are not legally married, have been selected for the present study. The 20 excluded families consist of five where only one parent is registered with the G.P., four where the mother is separated or divorced, three unmarried mothers, and two families where one parent has died. Failure to co-operate fully, which seems more common in families known by the G.P. to be disturbed, led to the exclusion of six further families.