I bought this book several years ago, so I’m not positive what I expected when I bought it, but somehow I had the idea that it was about the design of small things. After all, the cover on my edition (not the same as what is currently available) shows the first inch of a wooden ruler – enlarged at least 500%. A chapter on drinking water-related designs includes a section on the Dixie cup, and the chapter on the toothbrush mentions the toothpick in passing. But physical size is not what the title refers to.
The basic idea of the book is that no design is perfect, that it is not only difficult or impractical but impossible to have a perfect design. This is because there are always constraints, such as money or materials available, and competing design goals, such as esthetics and practicality. Thus the designer must make choices that sacrifice some of this to get a bit more of that, and the end design is a result of many such compromises.
The premise is easy enough to understand, and using it to examine how many common objects have been designed is very interesting. Sometimes one constraint is that the design has to take an existing object and modify it, which means that many choices have already been made and many possible designs eliminated from consideration. Or it may be that the design needs to allow for future easy modifications, which also forces certain choices and precludes others.
Constraints such as money, materials, and time are fairly obvious. But the designer has to take into account many other factors – safety regulations, the varying size of people who will use the object, the user’s ability to understand how to use it without extensive training, and how it compares with competitors’ products, to name just a few. There is also how to package it for sale, which is another whole design project.
Petroski examines the layout of a supermarket as another example of design, and shows how the seller’s objective – to get the shopper to walk past as many product displays as possible – is exactly the opposite of the buyer’s objective – to get as quickly as possible to the items on a list and out again. The familiar boxy stores where most of us shop is a compromise between the two.
He suggests reasons behind some apparently arbitrary design choices, such as doorknobs at about waist level but light switches at about a foot higher. He explores something many office workers have no doubt wondered about – why the number keys on a calculator are arranged in roughly the same shape but different order from on a telephone.
There are design improvements that make a product more comfortable or easier to use, but make it incompatible with older accessories. I would have thought of electronics as a good example, but Petroski makes it a chapter about toothbrushes. I had forgotten, until reading that section, the frustration of getting a nice new – and free – toothbrush from the dentist, and finding that it would not fit in the bathroom toothbrush holder.
(I could probably write my own chapter about the time I spent shopping for the toothbrush I have now. My requirements were that it have nice large holes for thick toothbrush handles, that it be freestanding rather than attached to a wall, and that it be both nice-looking and easy to clean. It took months after we moved into this house to find one that suited me – a very cute miniature sink with four holes arranged around the pedestal it stands on.)
There are so many good examples of the difficulties of design, and the tradeoffs required, that Petroski apparently couldn’t decide when to stop. As interesting as parts of the book are, it got tiresome to read after a while, and I lost track of how many times I put it down for weeks or months at a time before deciding I really was going to finish it. I wondered, toward the end, if perhaps it had been written originally as a series of articles, each of which would be interesting enough on its own.
Reading through the reviews at amazon.com, I found that my suspicion was correct. The editorial review from Scientific American mentions articles written months apart, which explains why there is so much repetition of the basic concepts about design, constraints, and compromise. Someone reading only one article would need that background, and even someone who had read previous articles might need a refresher.
When they were compiled into book form, however, some judicious editing would have been in order. I rarely have this opinion after reading a book, and find myself surprised at others who complain that a book I enjoyed was too long. But in this case it would have been much better if some examples had been culled, and some repetitions of the basic design principles removed from later chapters. (I find some satisfaction in finding that nearly all the customer reviews at amazon.com express similar complaints.)
I also realized, reading those reviews, that one of the other titles by Petroski sounded familiar. I looked downstairs, and sure enough, I found Invention by Design on my shelf. It gets better ratings (four stars vs three for this book), so I’ll have to check it out. Sometime – I’m not ready for another Petroski book just yet.