Kehlmann never intended to focus on historical fiction, and he has written a number of contemporary novels as well as plays and television shows. But seeking out figures from the past who allow him to explore ideas became something of a trademark almost two decades ago, after the unexpected mega-success, in 2005, of Measuring the World. For that novel, he fictionalized the lives of two early-19th-century German men of science, the naturalist Alexander von Humboldt and the mathematician Carl Friedrich Gauss, both obsessed in a cultlike way by a drive to capture nature in all its dimensions. The book sold more than 2.3 million copies in Germany, making Kehlmann a literary celebrity there and bumping Harry Potter from the top of the best-seller list.