PART I: INTRODUCTION; 1. Geographical epidemiology and ecological studies; 2. Small-area studies: purpose and methods; 3. Health and the environment: the significance of chemicals and radiation; PART II: DATA, COMPUTATIONAL METHODS, AND MAPPING; 4. Mortality data; 5. Cancer incidence data for adults; 6. Cancer incidence data for children; 7. Congenital anomalies; 8. Specialized registers; 9. Population counts in small areas; 10. Use of routine data in studies of point sources of environmental pollution; 11. Socio-economic confounding; 12. Use of record linkage in small-area studies; 13. Confidentiality; 14. Practical approaches to disease mapping; 15. Estimating environmental exposures; 16. Mapping environmental exposure; PART III: STATISTICAL METHODS; 17. Statistical methods for geographical correlation studies; 18. Bayesian methods for mapping disease risk; 19. Statistical methods for analysing point-source exposures; 20. Some comments on methods for investigating disease risk around a point source; 21. Methods for the assessment of disease clusters; PART IV: STUDIES OF HEALTH AND THE ENVIRONMENT; 22. Environmental epidemiology: a historical perspective: Guidelines for the investigation of clusters of adverse health events; 23. Studies of disease clustering: problems of interpretation; PART V: CASE STUDIES; 24. Childhood leukaemia around the Sellafield nuclear plant; 25. The epidemic of respiratory cancer associated with erionite fibres in the Cappadocian region of Turkey; 26. Soya bean as a risk factor for epidemic asthma; 27. The Sevesco accident; 28. Cancer of the larynx and lung near incinerators of waste solvents and oils in Britain; 29. A study of geographical correlations in China