The story of the Haber-Bosch process for creating synthetic ammonia, which is crucial for producing the fertilizer needed to feed the seven billion or so people on Earth today. In Hager’s phrase, it turns air into bread. It’s also the story of the lives of the men who created it, and its consequences for world agriculture and for Germany during the World Wars.
This was a very well-told story, and I’d recommend it to any history buff. Unlike many books on the history of technology and industry, it does a good job of explaining the science and engineering behind the invention (but it doesn’t get too technical for a general audience). It was a close runner-up for my favorite book I read in 2017.