Bookshops have rows of computer books, usually very thick paperbacks with yellow spines. I do not know why yellow is so popular, but the books are thick because there's so much to learn about computers. If we go back to the turn of the century, what did we need to know then?

The educated Edwardian needed to know about engines, and James Weir's French's Modern Power Generators (Gresham Publishing Company, 1908) was the book to read. With magnificent illustrations and enthusiastic text it described all sorts of engines: steam engines, gas engines, oil engines, petrol engines. The main point was that to get on in those days, you needed to know about engines. There was certainly a lot to know - though the author did not think highly of petrol engines; they were not as good as steam.

Engines were temperamental and there were not many of them. If your traction engine broke, you would not have a spare, so you needed to read this book to be able to fix it, Today, we have more engines around than Edwardians could have imagined, and they are far more reliable and far safer. My fax machine has a couple of engines in it, for example. And I have not used an oil can for ages.

Engines have disappeared from our consciousness. Engines are now designed so well that they work without continuous help from humans. Instead there are appliances, like faxes or washing machines, that do useful things. Most of us do not need to know a thing about the engines inside.

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Now come back to computers. What those computer books tell us is that today's computers do not work very well and they need our help. We must become computer literate, and learn how to format discs and do all sorts of technical tricks. But the engine analogy suggests that we only need to know so much because computers are not yet designed well enough. One day computers will disappear from consciousness.

It is clear to me that hidden computers will be a worthwhile advance. In the meantime, everyone who learns to be computer literate is delaying the day when personal computers will be properly made, easy to use, and will not come with a list of bugs you have to avoid.

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In fact there are already many hidden computers around us. You do not need to know about them, because they are designed to do their jobs well. ABS brakes save lives by making cars safer. You do not need to read a thick book before being able to use them properly. Sewing machines are another interesting example: here hidden computers give new freedom and creative possibilities to seamstresses. Music keyboards, though some might be said to be getting excessively complex, contain computers that work without you passing a computer literacy course.

The attraction of computer literacy is a snare. It is only because computer systems are so bad that so much time and money is wasted training people, including university staff and students, in their use. Moreover, if you accept computer literacy as a worthwhile goal, then you are saying in effect that you are responsible for how well you can use a computer. It would be better if manufacturers took greater responsibility for making their gadgets easier to use.

When I make these points, some people argue that PCs are a fact of modern life and we fail to become computer literate at our own peril.

But look back at the way the car industry operated in the 1960s. Many cars were dangerous because they were badly made. Manufacturers and insurance companies argued that drivers caused accidents. While drivers believed this, they would be happy paying extra to learn more about cars and driving, making themselves "car literate". Instead, with Ralph Nader's initiative, they started campaigning. Today's cars are considerably safer and easier to drive.

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Likewise the onus for better computer use should be very much on the manufacturers, not the users, nor even all those yellow-spined book authors. Each time someone becomes computer literate, manufacturers have another willing scapegoat for their bad designs.

What about actual examples? Try pressing 1+25 % on a calculator. I have three Casio calculators that respectively give the answers 1.25, 1.3333333, and 104. They cannot all be right. I have a fax that has commands that do not work; it is made by a French company that also makes missiles. The Internet is another good example. When people ask me how it works, I say that if it worked properly you would not need to know. Do you know how a telephone works? Does it matter? Do not feel you are inadequate, or need to become computer literate, when bad computer design is so widespread. Do not read another yellow book. If we could persuade them that it was worth their while, manufacturers could do very much better.

Professor of computing research at Middlesex University .Email Harold@mdx.ac.uk