Here are some autism statistics. During the 1990s, medical textbooks took the view that the "prevalence" of autism among children stood at between four and five per 10,000. By 2001, the Medical Research Council had published a report which suggested that the figure had risen to one in 166. Last year, the Office for National Statistics published the finding that 1 per cent of all school-age children in the UK featured somewhere on the autistic spectrum. Only last month, the Scottish Daily Mail carried a report of figures indicating that registrations of autistic children north of the border had risen from 820 in 1998 to 3,484 in 2005.
Something, as they say, is going on here. For whatever reason - and no one seems to be unchallengeably clear about what that reason is - autism is having a right go at our society. Analyse such figures how you will (and they cannot be attributed just to greater diagnostic efficiency), but it seems incontrovertible that the numbers of the autistic have multiplied by a huge factor in little more than a decade. One of the more predictable by-products of that increase has been an epidemic of autism books. There is a canon now, covering the autistic world from every conceivable angle. At the high end are the anecdotal/analytical accounts by parents of autistic children (class leader: Charlotte Moore); there are accounts written by people with autism (Temple Grandin, Donna Williams, Kamran Nazeer); there is popular science (Simon Baron-Cohen); and there are fictions (The Curious Incident of the Dog in the Night-time). All of these are worthwhile books, which might be said to offer something substantial to the sum of human understanding, not to mention the sum of wonderment.
Then there is the other stuff, the stuff that doesn't add much to anything, but might raise an empathetic sniffle and boggle a few minds. Nothing wrong with that, you might say, especially when you look at the stats. Ask any professional in the field of autism and they will tell you, sometimes with tears in their eyes, that the step that needs to be taken most urgently is to raise awareness.
But what exactly are we supposed to be aware of? Joe, which belongs at the "high" end of the aut-lit canon, suggests that we ought to be aware of what autism teaches us non-autistic people about our own capacities. Michael Blastland's meditation on his son's profoundly autistic condition begins like this: "It's a story of strange happenings and human riddles, it invites fantastical speculation and argues something brazen, preposterous even: that until you know Joe's unusual life, you won't fully understand your own."
And away we go into the strange, disconnected world of this "freckle-faced imp" who, given the choice, won't eat anything but Sainsbury's spinach and ricotta tortellini, and who has no time for anything else in life if there is a possibility, however infinitesimally small, that there is, on a shelf in a house down the road, a Postman Pat video. It is an extremely cruel world to behold, partly because of its excruciating banality. Joe doesn't do anything as amusing as mistake his dad for a hat. He certainly doesn't produce minutely accurate drawings of Palladian architecture, nor does he play the guitar like Jimmy Page.
The narrative of Joe, such as it is, is or-ganised around the removal of Joe from his family homes and his placement in a special school. We follow that agonisingly protracted process while Blastland pores forensically over what we can learn from observing Joe in all his dismal glory. He invokes Wittgenstein, Dennett, Baron-Cohen, Midgley, Locke, Macmurray, Sacks, Strawson. He goes for a spin with Francis Spufford's The Child That Books Built. He flees pathetically when Joe takes a leak in a toilet bowl on display at the local Do It All. We watch helplessly as Joe gets himself run over by a passing car while out stalking Postman Pat.
The upshot for Dad is an opening up of a universe in which the patterns of cognition - so casually experienced and then accepted by the rest of us - contrive to make a picture so deeply, complexly counter-intuitive that it threatens to overwhelm his sense of order and completeness in the world. Blastland's success is twofold. First, his book makes sense; second, he doesn't go mad with the effort of making it so.
In the end, it becomes clear that this book has two subjects. One is Joe himself; the other is Dad - or, more specifically, Dad's struggle with the idea of what Joe means. The word "love" is not much bandied about here. It is a book not ornamented with sentiment. Nor is it particularly concerned with how we, as readers, might feel either about the author or about his nominal subject. In a sense, Blastland has sacrificed one of the conventional rewards of writing - empathy - for a higher objective. It is a brave and frightening book in several ways.