For almost his entire professional life, from the late 1940s well into the 1990s, my father worked as an engineer in heavy construction. He helped build petroleum cooling towers and plants that processed nickel, the metal found in everything from rechargeable batteries to guitar strings. Over his life, he also took pictures—thousands of them—assiduously chronicling everything, including his dingy work sites. Among photos of our family vacations, he kept images of refinery operations, open-pit mines, and mining camps.