Over the past year, I’ve been reading books inspired by the centenary of World War I, a war with horrific casualties painful to contemplate. What helps in comprehending the scale of the slaughter is a book by one of Bill Gates’s favorite authors, the Canadian academic Vaclav Smil, Creating the Twentieth Century: Technical Innovations of 1867-1914 and Their Lasting Impact.

Smil leads the reader through the invention and development of electricity, oil production and distribution, the automobile, steelmaking, the telephone, the airplane and the production of synthetic ammonia — to his mind the most important because without it agriculture couldn’t feed the world’s 6 billion people.