Centuries ago, medieval builders of cathedrals were “elite workers [and] were well paid.” Their supervisor, a head mason, the elite of the elite, “commanded benefits far surpassing” others because of his superior knowledge: he knew how to craft archways and windows that withstood the weight of tons of stone without collapsing. Though the head mason was likely illiterate, he knew this because he had a rule of thumb.

It was, in the end, just a matter of simple engineering. It worked, says Hammack, because using rules of thumb can help attain the “best change in a poorly understood situation using available resources” – and we use such rules often, sometimes without even realizing it. Using rules of thumb, he says, is true every time anyone “has designed a solution to a complex problem... for millennia of human history.”

This rule of thumb method – this “engineering method” – is why landline receivers are as long as they are: female secretaries were the primary users of early business telephones; a series of rule-of-thumb measurements told inventors that the space between a woman’s ear and her mouth was just this distance. It’s how European automakers should make crash-test dummies. It’s why some women’s bikes are more comfortable to ride than others. Hammack cites a scientist who had access to rules of thumb and became “obsessed” with moving water in order to understand

the dynamics of fluid, and a scientist who figured out how one computer’s bits avoid colliding with other computers online. In all cases, the “engineering method” led to a solution.

Without it, says Hammack, humanity would be at a stand-still.

Sometimes, you’re too busy to notice.

There’s splendor in the everyday but so much goes unnoticed: the design of your belongings, the alcoves in a building, the lean of a bicyclist on the sidewalk. These are things that, once seen, can’t be unseen and in “The Things We Make,” your eyes will be opened.

But first: if you’re a tinkerer, you’re science-minded, or if you live by workarounds, author Bill Hammack makes you feel even smarter, explaining how you’ve become a link in history merely because you’ve used an interesting, ancient crowd-source that you (maybe) didn’t know existed. Go ahead, boast, but notice, too, that this book also begs readers to stop and appreciate the mundane and the magnificent. Someone else used an “engineering method,” too, and we can’t live without the fruits of their labors.

Be aware: this book takes a deep dive into science and it’s not for everyone. If you’re fascinated by engineering, though, find “The Things We Make” and tap into it.

”The Things We Make” by Bill Hammack Ph.D., The Engineer Guy

c.2023, Sourcebooks $26.99 272 pages