The term ‘Autism Spectrum’ currently embraces a cluster of conditions known as Autism Spectrum Disorders or ‘ASD’, that are characterised by impairments in social functioning, verbal and non-verbal communication, together with repetitive and stereotypical patterns of behaviour and interests. Impairments within each of these ‘core’ clinical domains can range in severity from mild to profound, and intellectual disability may be present in more severe cases. The classification of ASD broadly includes classic autism (childhood autism; autistic disorder), Asperger syndrome and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) (Levy et al. 2009). Classic autism is frequently diagnosed around the age of 3 (and may be diagnosed as early as 2 years of age) (Baird et al. 2003; Landa, 2008). Asperger syndrome often presents with more subtle symptoms, and is usually diagnosed later on in childhood (frequently around 11 years of age), and occasionally in adults (Howlin and Asgharian 1999; Toth and King 2008).

While the precise causes of autism remain a mystery, prevalence estimates have risen almost exponentially within the last six decades, making autism a major global concern. Initially considered rare, current estimates suggest that as many as 1% of children under the age of 8 years may have an autism spectrum diagnosis (Baird et al. 2006), with boys being diagnosed up to four times more than girls. More than half a million people are thought to be living with autism in the UK alone (National Autistic Society, 2007), and in the US autism is considerably more common today than it was in the 1980s (Yeargin-Allsopp et al. 2003).

There is widespread concern about the apparently growing prevalence of autism, although this increase may be due, in large part, to factors such as changes in diagnostic criteria and ascertainment practices. Public and scientific interest in the causes and fundamental nature of autism has never been stronger. Research in this field has grown exponentially in the last twenty years, with significant financial support in this area provided by Governments, Research Councils and private charities. Studies spanning a whole range of disciplines share the goals of elucidating the core phenomena and underlying aetiology, thereby informing therapeutic interventions, as well as offering valuable insights into normal functioning. Research by individuals and groups in the UK has played a leading role in addressing key unanswered questions about autism, including its causes and psychological substrates, the underlying brain mechanisms, and the most effective ways to work with and support people with autism and their families.

A major conference which we were privileged to organise in 2007, entitled: ‘Autism Research UK: from diagnosis to intervention’ hosted by the Open University and sponsored by the Medical Research Council, Wellcome Trust, Autism Speaks and a number of other organisations, provided an effective backdrop to this book. At this first national meeting of this scope, internationally renowned speakers and chairpersons convened with representatives from the Medical Research Council, the Wellcome Trust, Economic and Social Research Council, National Autistic Society and Autism Speaks for two days of discussion and debate aimed at elucidating ways forward in understanding the autism spectrum and helping affected individuals and their families.