The scientist Hendrik Lenstra owns no car, no computer, and no television. Instead, he possesses dozens of editions of Homer’s Odyssey. Lenstra is a mathematician who operates at the highest level of thought and has little interest in what is fleeting or fashionable in daily life. His passion for his field may sound abstract to outsiders, but its applications are very real: cash machines and aircraft control systems function thanks to the incomparable thinking of this great mathematician.