In a Different Key endeavours to tell the story of how autism went from obscurity to ubiquity. It sees early cases of the syndrome in the holy fools of medieval Russia, in feral children loping out of the European woods centuries later, and in an eighteenth-century Scottish gentleman who wore his wig backwards, filled his bedroom with twigs and feathers, and was obsessed with funerals. From this speculative prehistory, the book embarks on a detailed history of the past century, told largely through the personal stories of patients, doctors and advocates. Its forty-six chapters are themselves thickly stuffed with factual twigs and feathers.

Like any good story, In a Different Key has its heroes and villains. One hero is Leo Kanner, a humanist who first described the syndrome and was an unflagging supporter of autistic children and their parents. Another is Bernard Rimland, chief discreditor of the mother-blaming theories of Bruno Bettelheim, who emerges as something of a scoundrel. Bettelheim, chronicler of life in Dachau and Buchenwald, makes a strange bedfellow with Hans Asperger, after whom a high-functioning variant of autism was named. Asperger's collusion in the Nazi regime's euthanasia of disabled children was recently revealed. As though in shame, Asperger's syndrome was retired as a diagnostic category in 2013, nineteen years after it appeared.

The book's main protagonists are not professionals, but parents. John Donvan and Caren Zucker show that it was the fierce and sometimes despairing love of mothers and fathers for their affected children that drove many recent advances in treatment, social service provision, and public awareness. It is also striking how many of the psychiatrists and psychologists who pioneered the study of autism had autistic children themselves. A large fraction of the book is devoted to telling how individual mothers and fathers fought with indifferent authorities to create more humane institutions and more enlightened attitudes, to raise funds, and to seed new lines of clinical research. This part of the story is not blindly triumphal. Parents often form organisations that squabble and split, and they bicker over strategy and leadership, but it is in large measure their activism that gave autism the high public and scientific profile that it now enjoys.

For the historian of psychiatry, the story of autism is all too familiar. Where treatment is concerned, the narrative begins with bleak snake-pit asylums, where autistic children were left to rot among psychotic adults and intellectually disabled peers. It progresses through talk therapies aimed at defrosting 'refrigerator mothers', whose supposed lack of maternal love led children to withdraw into pathological inwardness. Behaviourists armed with electric cattle prods make an appearance, and fad therapies abound, with the deployment of LSD, megavitamins, pig hormones, dolphins, and swaddling in wet sheets. Throughout it all, the idea of a cure remains a tantalising and unrealised hope.

Theories of causation also display familiar pendulum swings between nature and nurture. Explanations that invoke congenital idiocy give way to psychoanalytic accounts indicting loveless families. Later accounts propose that autism originates in genetic and neural abnormalities, and these are in turn challenged by theories that blame environmental toxins. The book's recounting of the heated debates over the debunked role of vaccines in autism is gripping.

Leo Kanner, 1955 (via Wikimedia Commons)Most intriguing from a historical standpoint are the changes in how autism is defined. The idea of an autism spectrum, ranging from mild to severe impairment, arose in the 1980s and swelled the number of people who fell within the elastic boundaries of the diagnosis. The recognition of Asperger's syndrome, in which high intelligence often accompanied mild autistic features, contributed to this inflation. The book demonstrates how prevalence rates for autism are inherently slippery and contestable, and how claims of an epidemic are therefore difficult to evaluate. More radically, it also examines the idea of 'neuro-diversity', which urges that autism should be seen not as pathology, but as an alternative way of being: as difference to be valued, rather than disability to be overcome.

The book is not without flaws. It is highly US-centric, aside from occasional transatlantic jaunts to London. Australia features as the site of the 1980s 'facilitated communication' scandal, where a revolutionary technique that seemed to enable severely autistic people to converse was proven to be as invalid as the Ouija board, and for the same reasons. Any reader seeking an exposition of modern scientific knowledge on autism will be disappointed. Donvan and Zucker display some journalistic tics, repeatedly ending sections with a staccato paragraph of a single sentence – 'No fax ever came.' – or even a single word: 'Fear.'

These are minor irritants in a book that succeeds on its own terms by offering an engaging tour of an unfamiliar landscape. The autistic celebrity Temple Grandin told Oliver Sacks that being a person with autism is like being an anthropologist on Mars. This book allows the Martian majority to see some of our fellow aliens in a new light.