THREE DECADES ago, a German history professor listed 210 proposed explanations for the fall of the Roman Empire. The remarkable array included such fanciful causes as Bolshevism, public baths, hedonism, the pressure of terrorism and, most famously, lead poisoning. The last explanation has been discredited. It is highly unlikely that lead water pipes caused the ...

The best way to read Ezra Klein and Derek Thompson’s new book is to take the authors at their word. Abundance is what is usually called a “policy book,” but Klein and Thompson don’t quite offer a traditional policy agenda. Instead, the authors begin and end with a question that is also a concentrating lens. “Can we ...