William Keith was a Scottish-American painter famous for his California landscapes. He is associated with Tonalism and the American Barbizon school. Keith was an early environmentalist who developed a lifelong friendship with the famed conservationist John Muir. The two Scottish immigrants took camping trips together in the High Sierra, saw each other when Muir was in San Francisco and helped inspire each other's work. The idea for the Sierra Club was first formed in Keith's studio during conversations with Muir, Dr. Joseph LeConte, the first president of the University of California, and Warren Olney, a prominent San Francisco attorney who was also a Trustee of Mills College. Muir's concern with scientific accuracy reinforced Keith's early training as a wood engraver in encouraging him to reproduce the exact topography and details of a landscape early in his career.
Two lengthy sojourns in Europe, each bracketed by visits to the eastern United States, had particularly strong effects on Keith's artistic development. In 1869, three years after he first began exhibiting and selling paintings, he left San Francisco for visits to New York and Paris and art study in Dusseldorf, Germany. By the time he returned to San Francisco in 1872, his painting style had changed considerably. The abundance of foreground detail typical of early works had been replaced by looser, sketchier brushstrokes. In the 1870s, Keith had established his reputation as a painter of grand panoramic landscapes, often of the High Sierra or other mountainous countries, and sometimes as large as six by ten feet. This type of painting could serve both as a document of a specific locale and as an homage to divine creation in the form of the impressive American wilderness. By the 1890s, Keith typically painted forest glades at sunset, with other kinds of religious overtones. He believed that his late, dark, indistinct works better suggested the spiritual reality that lay beyond the surface forms of nature.