Call me sad, but when I was asked to review Asperger Syndrome my heart skipped a beat. The reasons: increasing numbers of people are being referred to mental health services for advice on ‘Asperger's’, yet little is known about the disorder; the editors of this book are pre-eminent in their field; and the people contributing chapters include outstanding researchers and affected individuals. So, what do we know already, and what was I hoping to learn?

We know that autistic disorder (comprising the genetically related subtypes of classic autism, high-functioning autism and Asperger syndrome) is a developmental neuropsychiatric condition and that it is associated with a significant increase in social exclusion and mental health problems. Core symptoms include impaired development of reciprocal social skills and communication, ritualistic/compulsive behaviour. Individuals with classical autism also have delayed language development and most have learning disability. However, around 25% are classified as high-functioning, because they have normal or superior general intellectual ability, in spite of having a history of early language delay. Individuals with Asperger syndrome have no history of language delay and have normal or superior intellectual abilities, but also show the characteristic impairments in reciprocal social interaction (Reference WingWing, 1997; Reference GillbergGillberg, 1998). Thus, in both high-functioning autism and Asperger syndrome there is a significant dissociation between cognitive and social skills.

There are also many things we do not know about Asperger syndrome. These include its genetic and neurobiological determinants, comorbidity with other mental health disorders, response to treatment, long-term outcome and the health and social costs to the person and their family.

Does this book help illuminate these issues and would I recommend it to researchers, clinicians and people affected by Asperger syndrome? My answers are “Well, sort of” and (respectively) “Yes”, “ No” and “No”. The chapters on historical aspects, differential diagnosis, neuropsychology, brain imaging, language disorders and non-verbal learning disabilities are illuminating, and the contributions by affected people are valuable. However, there is little new information on issues of assessment, treatment or outcome. Also, some chapters seemed to be based mainly on work in classical or high-functioning autism. This is almost inevitable because our knowledge about Asperger syndrome is relatively limited. None the less, I could not help feeling that the book, while well intentioned and responding to our demand for more information, is slightly premature, given the current level of knowledge.