In 1877 William H. Rau, the son of Philadelphia photographer George Rau, purchased the stereograph company of his father-in-law, William Bell, a photographer with the U. S. Geological Survey. Rau continued to publish stereographs as well as lantern slides under his name, though some of the photographs were probably taken by assistants until the company was acquired by Underwood & Underwood in 1901. In 1898 the company's most popular subject was the Spanish-American War, including scenes such as this one of a gunner aboard the USS Iowa. Part of Rear Admiral William T. Sampson's fleet, the Iowa won fame in the battle of Santiago de Cuba. The popularity of the stereocards led to the publication of an illustrated supplement to Rau's annual catalogue.
Rau was appointed official photographer of the Lehigh Valley Railroad in 1895. Traveling in a lavishly equipped passenger car, complete with a darkroom, parlor, and roof-mounted camera platform, he surveyed the length of the line, from New York City through Pennsylvania to upstate New York. Using familiar conventions of earlier western landscape photography, Rau combined scenic views with details of industrial progress. Rau's photographs described a modern landscape with little nostalgia for an Edenic past, showing, in the words of the railroad company report, "that which the regular traveler flying by on a fast express cannot see."
As part of the raliroad's campaign to promote the region to businessmen and tourists, many of the photographs were printed with the slogan "Lehigh Valley: The Switerzland of the United States."
Merry A. Foresta American Photographs: The First Century (Washington, D.C.: National Museum of American Art with the Smithsonian Institution Press, 1996)