Introduction to the Iowa 500. Historical perspective. Background findings in course and follow-up of the affective disorders and schizophrenia. The family background in the major functional psychoses. The Iowa 500 genesis. Real people: histories and verbatim interviews. The follow-up of untreated patients: the course of the illness unaffected by effective therapy. Families: familial psychiatric illnesses obtained by systematically obtained family histories. Special aspects: life events, early parental loss, premorbid asociality, clinical characteristics, outcome after short follow-up, heterogeneity in bipolar illness, subtyping schizophrenia, delusional disorder, affective symptoms in schizophrenia, sporadic depressive disease. The gospel according to field work: methodology of follow-up and epidemiological findings. What the future held: 30--40 year course and outcome in patients according to final diagnosis. Familial psychiatric illness in schizophrenia and the affective disorders: psychiatric illness in relatives obtained by personal examination. Early clinical and family history findings in light of the final Feighner diagnosis: admission clinical picture and family history relevant to follow-up diagnosis. Zero -- symptom schizophrenia: symptoms present in schizophrenic patients after a 30 -- 40 year follow-up. Diagnosis and classification of the affective disorders and chronic nonaffective psychoses: the contribution of the Iowa 500 to diagnosis and classification. References. Appendix I: The Iowa 500 -- bibliography. Appendix II: Code book -- index admission and chart follow-up for the Iowa 500 Study. Index.