Thomas Cunningham Porter (1860-1933) was a science master at Eton College, today known for his contribution to the Ferry-Porter law. In the late 1890s he visited the United States, travelling to Yellowstone Park, Yosemite, and Colorado. He illustrated this narrative of his trip with numerous stereoscopic plates, and the book is supplied with a small stereoviewer for the purpose of examining the images. The book concludes with several appendices of a scientific nature, including a theory of the Geyser, and physiological observations.