Every time I set out to visit a country in the NATO alliance when I was Supreme Allied Commander, I’d try to read a book that could help me understand the history, culture and zeitgeist of the place. It could be a novel by a native writer, a history or a work of historical fiction. Can you really understand France without reading Camus and Sartre? To comprehend Russia, including the mindset of Vladimir Putin, I’ve found more illumination in Pushkin, Dostoyevsky, Tolstoy and above all Gogol than in most CIA reports, with all due respect to the agency.

So with the end of 2020, I want to offer five books that have helped me make sense of a confusing world in the past year.

Let’s start with a sweeping look at some of the most important global trends: "The New Map: Energy, Climate, and the Clash of Nations” by Pulitzer prize-winning analyst Daniel Yergin (disclosure: Dan is a colleague of mine at the private equity firm Carlyle Group). Yergin’s 1990 book about the oil industry, "The Prize,” is a standard text in most graduate schools of international relations. By the way, the world still depends on oil, gas and coal for 80% of its energy — roughly the same as it did when he wrote the book 30 years ago. But so much else has changed.