Vaclav Smil is my favorite author, but I sometimes hesitate to recommend his books to other people. His writing, while brilliant, is often too detailed or obscure for a general audience. (Deep dives on Japanese dining habits or natural gas can be a tough sell for even the smartest, most thoughtful readers.) Still, I’m a big enough fan to keep telling my friends and colleagues about his books, even though I know most of them won’t take me up on my recommendations.

That’s why I was thrilled when Vaclav released his most accessible book yet. Numbers Don’t Lie: 71 Things You Need to Know About the World, which came out last fall, takes everything that makes his writing great and boils it down into an easy-to-read format. I unabashedly recommend this book to anyone who loves learning.

This is probably the most information Vaclav has ever put in a book, and yet it’s by far the most digestible. Each chapter is just a couple pages long and covers one of the 71 facts mentioned in the title. Here are three that I found particularly interesting:

1. You can thank sweat glands for our big brains.

Humans are the grand champions of sweating. We’re able to remove heat from our bodies through perspiration better than any other mammal (partly because we have very little hair). Vaclav writes, “In the race of life, we humans are neither the fastest nor the more efficient. But thanks to our sweating capabilities, we are certainly the most persistent.”

Our ancestors had better endurance than the animals they hunted for food, which allowed them to run down rich sources of protein that provided the fuel for our brains to develop. The next time you feel miserable on a hot day, just think about how all the sweating you’re doing is the reason you’re so smart!

2. The French are drinking a lot less wine than they used to.

“Viticulture, wine-drinking, and wine exports have been long established as one of the key signifiers of national identity” in France, writes Vaclav. In 1926, the average French person drank an impressive 136 liters of wine (or more than 35 gallons). But by 2020, that figure had shrunk to just 40 liters.

The idea that French wine consumption is now a third of what it was a century ago is amazing to me because of what it might reveal about how society is changing. While young French people are drinking less alcohol overall, the consumption of mineral and spring water has doubled since 1990. Does that mean the French are becoming more health conscious? Was life just so bleak in the 1920s that people had to drink? Have people replaced drinking wine with other diversions like watching TV or browsing the web? I love how this book forces you to think about the story behind a seemingly niche statistic.

3. The 1880s might be the most consequential decade in human history.

One of my favorite things about Vaclav’s writing is his ability to put history in context. Although it’s tempting to see the era we’re living in now as a time of unprecedented innovation, he argues that the 1880s saw the real technology boom. The decade saw the discovery of electricity and the internal combustion engine—along with somewhat less consequential but still important innovations like the ballpoint pen, the modern bicycle, and Coca-Cola. If you want to read more about the inventions the 1880s gave us, you can download a free chapter here:

Vaclav believes that progress comes in fits and starts rather than in a constant stream. Humanity will go through long periods where everything stays the same, and then a new invention will come along that sets off a rapid period of change. For example, Thomas Edison’s discovery enabled the creation of the electric elevator in 1889. This, in turn, let us build taller buildings like skyscrapers since people would no longer have to rely on stairs to reach the top floor. City skylines would look a lot different today if it weren’t for the 1880s.

If you read Numbers Don’t Lie and like it, you might also enjoy Vaclav’s latest book Grand Transitions. Numbers Don’t Lie(He is nothing if not prolific, having released two books during the pandemic.) It looks at how societies are shaped by shifts in demographics, agriculture, economics, and energy use. It’s not quite as accessible as , but the subject matter is so interesting that I think people will find it worthwhile.

Vaclav finds as much joy and fascination in looking to the past as anyone else I know. As someone who tends to be optimistic about technology—maybe even too optimistic at times—I appreciate how his natural skepticism about future innovation keeps my outlook realistic. If you’re looking for someone to help you understand how history ties together, you can’t do better than Vaclav—and Numbers Don’t Lie is a great place to start.