This volume contains the Proceedings of a Conference on Scientific Aids in Hospital Diagnosis held at Oxford in April 1975. The Conference, organised on inter-disciplinary lines, was the fourth to be organised by the U. K. Liaison Committee for Sciences allied to Medicine and Biology (SAMB). The subject matter is divided into six sections: Investiga- tions in Pathology, Radiation Diagnostics, New Diagnostic Tech- niques in Special Departments, Clinical Measurements in Wards, Coordination and Communication of Results, and finally Ergonomic Contributions to Medical Diagnosis. Session IV may be found of particular interest as it puts the point of view of the nurses who have to operate so many of the new machines and pieces of equipment, often under stressful conditions. We were fortunate in having as our Guest Speaker, Sir George Godber, Former Chief Medical Officer to the Department of Health and Social Security. Sir George's career has spanned the time during which very many scientific technqiues have been in- troduced into medicine and few people could be better qualified to give an overall picture of the present situation.