Fifty years after the spectrum of autistic disorders was first recognised, the condition continues to baffle researchers, evading definition nearly as thoroughly as it does a cure.
The National Autistic Society sums it up as "a lifelong developmental disability which affects social interaction, social communication and imagination". The condition often features repetitive behaviour patterns, and is thought to affect around 520,000 people in the UK.
While a small proportion of autistic people may have islands of outstanding ability (the draftsmanship of Stephen Wiltshire and the profitable arithmetical skills displayed in the film Rain Man are well-known examples), life for many sufferers is dominated by varying degrees of confusion and alienation - even downright terror of human society.
The NAS is always at pains to stress that, for the time being, autism is incurable. However, much publicity has been given in recent years to a system of training and management practised first in Japan and subsequently in the United States by the Higashi schools. This year, two schools using versions of the Higashi method are scheduled to open in Britain - one in Staffordshire and the other in Berkshire.
There have also been positive developments in diagnosis - developments which should mean that parents are less likely in future to suffer the frustrations highlighted in recent surveys.
The Check List for Autism in Toddlers (CHAT), developed by Dr Simon Baron-Cohen at Cambridge University, picks up on such early indicators of autism as poor eye contact. In some parts of the country, health visitors automatically perform this 10-15 minute test at 18 months, and the NAS is campaigning for this to become standard practice.
The society is about to launch a system which will enable others to apply the principles developed at its own diagnostic centre at Bromley in Kent. "It goes under the unlikely acronym of Disco," says Paul Cann. "Disco doesn't quite stand for Diagnostic Interview Schedule for Communication Disorders. But you can make up most of the letters there."