More a space than a place, the ocean had long occupied the American imagination as a geographical border to be crossed. The process of coming to know of the ocean as a place began in the nineteenth century, but it was not until the twentieth century that the ocean---the ocean beyond America's shores---became known as a part of nature, as a wilderness. This dissertation provides a cultural history of those explorers and naturalists who did the work of filling in the "blank spaces" of the ocean realm. More important, they were largely responsible for making the ocean known to the American imagination as a place be managed and conserved, and as a place of beauty and recreation. This dissertation ends just at the point that Americans began including the ocean within a wider environmental concern---as a geography to be preserved. The oceanic naturalists discussed here were partly responsible for ensuring that the ocean would be included within the politics of modern environmentalism. They ventured into territories to examine a wide range of oceanic phenomena and then constructed representations for popular audiences back home.

The subjects of this dissertation were among the most popular spokespersons for the oceanic environment between 1910 and 1960: Roy Chapman Andrews, Robert Cushman Murphy, William Beebe, Rachel Carson, and Eugenie Clark. Two organizational histories---The Explorers Club, and the Pacific Science Board---are also provided to add context to the culture of natural history in which these naturalists operated. Interdisciplinary in scope, this project addresses critical issues in the history of science, environmental history, and the literary studies of the environment.