The value of this book is revealed by its subtitle: Emerging Applications. This is a book about the cutting edge of expert psychiatric testimony and could not have been written 20 years ago. Its relevance is a consequence of a burgeoning of knowledge and the extent to which this has given rise to complicated legal issues, some of which have gone all the way up the appeal process.

The topics covered in Psychiatric Expert Testimony fall into two broad categories – human development and its deviations, and scientific and technological advances. Examples include: the developmental approach to culpability in adolescents; the testimony of child victims of sexual abuse; the effects of stress and trauma on the developing brain; autistic spectrum disorder in the criminal justice system; the use of functional magnetic resonance imaging (fMRI) for lie detection; sleep disorder and criminal responsibility; neuroimaging and criminal culpability; chronic traumatic encephalopathy; and designer drugs and criminal responsibility. Many of these topics represent uncharted legal waters for most expert psychiatric witnesses.

No psychiatrist should venture into these waters without understanding the potential hazards. Such hazards include offering testimony that is too prejudicial, or the temptation of using the findings of scientific discoveries that are ahead of their time in terms of scientific weight and fall foul of the law's requirement that expert evidence must reach a certain reliability threshold to be admissible. Psychiatric Expert Testimony is full of up-to-date science and examples of cases that illustrate how perilous these waters are. Although the legal cases are mainly North American, the issues are similar to those being encountered in jurisdictions elsewhere.

Watson & Weiss eschew a prescriptive approach and instead provide the material which will allow the reader to ‘incorporate current practice and case law into reasonably evidence-based reports and testimony’. A psychiatric expert would be unwise to offer testimony in any one of the areas covered in this book without having read the appropriate chapter and the introductory chapters, not least because their cross-examiner and the expert for the other side may well have done so.