This is the one book Bill Gates says you should definitely read this summer

In a new blog post, Gates recommends another Smil book because he says it’s more accessible. Called Numbers Don’t Lie: 71 Things You Need to Know About the World, it’s less like an engineering textbook and just a collection of thought-provoking facts presented in one or two-page chapters. Smil looks at questions like whether your car or your phone is worse for the environment, how humans developed big brains (he credits our unique ability to sweat, which allowed early humans to hunt longer and eat more protein), and how much the world’s cows collectively weigh (answer: more than any other animal on the planet).

Smil also takes a clear-eyed look at how challenging it will be to pull the world away from fossil fuels quickly enough to address climate change. It would be incredibly difficult, he says, to limit global warming to 1.5 degrees Celsius, the most ambitious goal in the Paris climate agreement. “That is not impossible—but it is very unlikely,” he writes. “Reaching that goal would require nothing short of a fundamental transformation of the global economy on scales and at a speed unprecedented in human history, a task that would be impossible to do without major economic and social dislocations.”

Gates is very aware of the enormous challenge of making the necessary climate transition. (Here’s an excerpt from his own recent book, How To Avoid A Climate Disaster.) But he’s also an optimist, a believer in the power of new technology to solve problems, and a big investor in climate tech, so he says Smil’s approach of questioning everything helps him stay grounded. “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,” Gates writes.