Homelessness is a universal phenomenon. Virtually all countries around the globe will experience some degree of homelessness. The numbers will depend upon several political, social and economic factors. The traditional stereotype of a homeless individual as a Skid Row alcoholic has given way to homeless individuals, young and old, black and white, male and female with homeless families and sheltered accommodation of variable quality. Not all mentally ill are homeless and neither are all homeless mentally ill. However, there is a very clear association between the two.

The temptation to look at only one module of homelessness and singular linear causality leading to homelessness must be resisted. Different countries have different experiences of homelessness and have devised different methods of dealing with the problems of mentally ill homeless individuals, but whether all models can be transported and used across cultures remains to be seen. However, the need to learn from others' experience, their good models and mistakes makes it possible to see the problems of mentally ill homeless in a completely different light.

This is the first volume to bring together authors from different countries with a great deal of clinical and non-clinical expertise on the double helix of homelessness and mental illness. I have been very fortunate in gathering a group of dedicated authors who have not only offered advice but have delivered their contributions in a way that made putting this book together a pleasure. I am particularly indebted to Drs Jane Marshall, Max Marshall and Philip Timms for their advice and support. I am grateful to Dr Richard Barling and Dr Jocelyn Foster of Cambridge University Press for their patience and guidance.