I preface this book with a number of explanations. First, why a fifth edition in view of the fact that longer intervals have elapsed between the publication of some of the earlier volumes? The answer is simple, and I hope acceptable. The pace of change in criminal justice and forensic mental health (or ill health as I prefer to describe it) has been increasingly rapid – as is the accumulation of new research and other data. We have seen amending legislation on extended sentences for public protection – sexual offences, changes in mental health law and proposals for reform of the law in relation to homicide being just a few examples. Some of these could only be adumbrated in the fourth edition. This edition will examine, where possible, some of the effects of these changes. A number of them have occurred as a result of somewhat premature implementation – an unseemly rush to legislate; this phenomenon will be mentioned in this fifth edition. Second, why insert a subtitle? With the exception of the first edition, few of the previous editions carried one, so why now? I have decided that this fifth edition should continue my own personal explorations in the field of clinical criminology, this term being an accepted one for the various matters discussed in the following pages. My new subtitle is An introduction to clinical criminology.