WHEN DOUGLAS BIKLEN and others at Syracuse University's Center on Human Policy coined the term "handicapism" a few years ago, they defined it as a "theory and set of practices that promote unequal and unjust treatment of people because of apparent or assumed physical or mental disability." It promotes myths like these: that people with disabilities can never be independent and must lead very different lives; that they are tragic figures and need our pity; that they're much happier with their own kind; that the nonhandicapped have a moral obligation to help the handicapped; that retarded people are mentally ill, sexually agressive, eternal children; that they are all lovable and friendly; that all deaf people are unable to talk, that they are not very bright; that all blind people have very good memories, etc.

For those who worry that such handicapist myths are as firmly entrenched and as in need of routing as racism and sexism, Janet Kamien's What If You Couldn't ...? is another welcome effort to help children understand and accept the "differentness" or people with disabilities. An associate director of the Children's Museum of Boston, Kamien has worked with disabled children and trained interns to work with them. Her approach is to encourage empathy. She asks her young readers to imagine what it would be like to be disabled -- to be blind, for instance, or deaf, or crippled, or retarded, or emotionally disturbed, or learning-disabled.

The reader is instructed to put on a blindfold and, with supervision, to take a walk around the house, then down the street; one by one he learns about the aides and assists available to blind people that make mobility, reading -- all of daily living -- possible. Somewhat more difficult is the job of describing how it feels to be mentally retarded. But she does it nicely, describing the many steps necessary to learn a concept such as "hotness" -- simple, perhaps to the reader, but not simple at all for some retarded children.

And so it goes for each of the disabilities. We see how each creates limits, how those limitations feel, how others are liable to react, and what sorts of props and systems can make the disability less handicapping.

The book is full of important information which, of itself, could go a long way toward helping nonhandicapped children feel less awed, anxious or uncomfortable in the presence of disability. However, I wish Kamien had gone a step further and confronted the common misconceptions and the put-downs so often endured by "special" children at the hands of their peers. For example, small children often confuse disability with sickness and worry about catching it. Most children feel sorry for disabled people and, thanks to bad examples set by so many adults, feel pleased with themselves for responding with pity. Also, children fall easily into name-calling, "retard" being a favorite pejorative. Already embued with some measure of handicapism, kids need more than information to make them empathize with likely victims of their scapegoating. They need to read about, think about and discuss their own and other's put-downs and the motivations for them. Kamien hints at the name-calling problem but skirts it.

Parents, teachers, librarians, or anyone introducing this book to children will be pleased for the most part with its good readable style. But I have some quarrels with the book's design. The text is interrupted continually by paragraphs in smaller print which contribute unconnected points of information, and the logic of the intrusions is often hard to discern. This format is further complicated by overlong italicized captions beneath some of the illustrations.

Despite these problems, What If You Couldn't ...? makes a real contribution to our efforts to break down invisible barriers. Attitudes, after all, can be the most formidable obstacles. Providing information about how it feels when something about a person's body, mind or emotions is different is a necessary step towards helping children understand and accept their handicapped peers.