It's written from a parent's point of view, and mostly (it seemed to me) for an audience of other parents, but there's a lot in it to interest people outside that core audience, too. There's a lot of historical stuff about the first descriptions of autism, and about how psychologists have tried to understand it over the past six decades or so; Grinker's father, grandfather and great-grandfather were all psychoanalysts (psychiatrists, too --- his grandfather founded the Archives of General Psychiatry), so he has a very strong grounding in the history of psychology and psychoanalysis.
He also addresses the question of whether there is or is not an autism epidemic, going into some detail about how diagnostic categories have changed, how the availability of special-education services varies by diagnosis, and how the ways of measuring the prevalence of autism have changed.
The first edition of the DSM to have "autism" as a category was the DSM-III, published in 1980. The criteria for "Infantile Autism" were fairly specific:
A. Onset before 30 months of age
B. Pervasive lack of responsiveness to other people (autism)
C. Gross deficits in language development
D. If speech is present, peculiar speech patterns such as immediate and delayed echolalia, metaphorical language, and pronominal reversal.
(There was also a category for people meeting all of these criteria, but with the condition not appearing until after 30 months of age; there were also "residual state" diagnoses for people whose speech problems or unresponsiveness had lessened to the point that they no longer met the above criteria).
The DSM-III-R criteria were somewhat looser, getting rid of the age-of-onset criterion and collapsing the "residual states" into Autistic Disorder itself --- you could have an autism diagnosis even if you did not currently meet all the criteria, as long as you had met them before.
The loosest criteria of all were those of the DSM-IV, which I had already known, but what I didn't know was that their flexibility wasn't all by design:
[T]here was an error in the final manuscript. It is not well known, even among experts, but in 1993, when the authors of the child psychiatry section of the DSM were editing the proofs of the new DSM-IV, which would be published in 1994, they missed a critical mistake. For PDD-NOS, the largest group of autism spectrum disorders, they had intended to write as the criteria, "impairment of reciprocal social interaction and in verbal or nonverbal communication skills." A different text was accidentally published. It said, "impairment of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present." The authors had wanted someone to qualify as autistic only if they had impairment in more than one area, but the criteria, as published, required impairment in only one area for a diagnosis of PDD-NOS.
Another interesting aspect of his discussion of autism diagnoses hinges on the different priorities of clinicians and researchers, and his idea (well-buttressed with quotations from prominent psychiatrists) that autism diagnoses are often made not because "autism" accurately describes the child being evaluated, but because they think the special-education services targeted at autistic children will do the most good for that child. That would go a long way toward explaining the "diagnostic substitution" that's occurred over the years, with more children being classified as "autistic" at the same time as fewer children are being classified as having plain old intellectual disability. (Grinker also includes a parallel instance of a diagnostic category that no one would argue is actually becoming more common --- traumatic brain injury --- becoming more widely used over the same period of time, due to changes in the U.S. Department of Education's disability coding system).
The part of the book that was most interesting to me was the series of chapters on cultural attitudes toward autism in three other countries: India, South Korea and South Africa. For each country, Grinker profiles one or two families with autistic children, usually starting with the mother, and letting her tell the story of how she came to suspect that there was something different about her child, and how she overcame varying degrees of stigma, disbelief and lack of services to get her child therapy, special education and a place to live when she could no longer take care of him/her.
We meet Golden and Suzanna Khumalo, and their son, Big Boy, who moved from Soweto to Cape Town in South Africa to get their son to a psychiatrist, and away from Golden's parents and ex-wife, who blamed Big Boy's autism on, respectively, displeased ancestors and witchcraft. We meet a woman named Merry Barua, in Delhi, India, who founded a school for autistic children called Open Door, which she began for her own son, in the absence of any other school that met his needs. We also meet two families from South Korea: a woman named Seung-Mee, with an autistic daughter named Soo-Yong, who joined a Christian church because the church members were the only people she ever met who really seemed to accept her or her daughter, and another family with three children, one of whom is autistic and kept hidden from the world. Autism is a highly stigmatized condition in South Korea, and one that reflects poorly on an entire family, so often doctors will diagnose a child with an attachment disorder instead. Grinker does think it's getting better for autistic people there, though: a recent film about an autistic marathon runner is lessening the taboo somewhat, and giving people the idea that autistic people can do more, and have fuller lives, than they had previously thought.
There was one aspect of autism that I thought this book didn't go into very much, though: he doesn't include very many quotes from autistic people themselves. (I can only remember one, actually --- at the very end, talking about a college class on autism he taught where one of the students had Asperger's syndrome). This didn't bother me as much as it might have, since he wrote about his autistic daughter Isabel in such an empathic way; rather than simply describe her behavior as if she were some kind of space alien, he gives context for everything she does, and tries to convey something of her feelings. He lets us see her grow up, learn things, acquire skills, and pursue her special interests. He writes from a caregiver's point of view, and everyone he interviews is also a caregiver, but he writes about his daughter with such love, respect and understanding that I never got the feeling that he thought of her as a burden, as an extension of himself or as anything but her own person.