A shift in attention from land to sea is under way in several fields simultaneously. Archaeology has moved offshore, revealing previously unknown aspects of prehistory that had been lost to rising sea levels. Anthropology, which got its start on islands, now focuses on the seas between them. Maritime history, once largely about what has taken place on the water’s surface, is now concerned with life in the ocean itself. It is rapidly merging with marine biology, becoming indistinguishable from natural history. What had been a blue hole in environmental history is beginning to be filled by studies of particular species of fish and marine mammals. Even more recently, we have begun to explore the history of ocean currents, tides, and even waves, phenomena once thought to be timeless, like the “eternal sea” itself.

The historicization of the oceans is one of the most striking trends in the blue humanities. History no longer stops at the water’s edge. The Mediterranean Sea was an organizing concept for ancient historians, and now Atlantic history is an established part of early modern scholarship, with the Pacific looming large in contemporary studies. Some global historians, in fact, chafe at oceanic as well as continental divisions, arguing that our globe is dominated by one great seamless body of water, covering seven-tenths of the planet’s surface and affecting weather, climate, and life on land as well as at sea. Geography has finally begun to take an interest in the oceans. Beginning with Philip Steinberg’s The Social Construction of the Ocean (2001), a vast area of exploration has opened up. Historians of science have come to recognize how the voyages of the early modern period produced what the environmental historian Richard Grove showed were the first glimmerings of ecological thinking, when mariners discovered the damage that invasive species of plants and animals could do on small islands around the world.

Sea stories, chanties, and marine painting are by no means new, but it is only recently that they have been subject to academic scrutiny. The seascape, once a minor genre in art history focused mainly on ships and harbors, took on new interest when nineteenth-century painters like J. M. W. Turner and Winslow Homer pioneered the representation of light and movement on canvas, “pure seascape,” as some critics have called it. Comparative literature scholars like Margaret Cohen have shown how sea stories, concerned originally with the mechanics of sailing, came in the eighteenth and nineteenth centuries to focus on the ocean itself, turning it into a space within which to imagine modernity. The modern novel was born at sea with Robinson Crusoe, reaching a new level of metaphysical sophistication with Moby-Dick, and carried forward by the watery science fictions of Jules Verne. Melville’s observation that “meditation and water are wedded forever ” anticipated by almost a century Carson’s evocation in The Sea Around Us (1951) of humankind’s mental and imaginative turn to the sea. In what is now being called “ecoliterature,” we are discovering the scientific side of writers like John Steinbeck, whose close collaboration with the naturalist Ed Ricketts in The Log from the Sea of Cortez, published in the same year as Carson’s classic, can be seen as one of the first examples of this genre.

The emergence of the blue humanities is a belated recognition of the close relationship between modern western culture and the sea. Before the nineteenth century, attitudes toward the oceans were more utilitarian than aesthetic. The sea was portrayed as dangerous and repellant, ugly and unfit for literary or artistic representation. Oceans were explored as a means to reach distant lands, and little attention was paid to the waters themselves. It has been said that “the deep sea made hardly any impression. . . . Even oceangoing explorers were more land than ocean oriented; they used the sea merely as a highway to get to the next landfall.” This was a discovery more by sea than of the sea.

Early modern science knew much more about the heavens than about the oceans; and more attention was paid to extracting the wealth of the seas, namely fish, than to the waters themselves. All that lay beneath the surface—The Deep—was thought to be an unfathomable abyss, impenetrable and unknowable, a dark dead zone that trapped all that sank below the surface, never revealing its secrets. Until the nineteenth century, notes writer James Hamilton-Paterson, our understanding of the sea was “literally superficial, . . . a navigable surface, obviously, above an abyss.” Early modern sea fiction and painting were surprisingly impoverished when it came to the oceans themselves. The focus was almost entirely on the ships and the skills of the men who manned them, with the sea itself almost an afterthought. What might be called the second discovery of the sea, beginning in the late eighteenth century and accelerating in the nineteenth and twentieth centuries, produced a vast expansion of scientific and humanistic knowledge of the sea as a three-dimensional living thing with a history, geography, and a life all its own. Modern times accomplished what no other era had even attempted, namely the discovery of the temporal and spatial depth of the sea. Darwinian evolutionary science came to recognize that waters gave birth to all life on earth, including our own. Archaeology exploded the finite chronology imposed by Biblical orthodoxy and ultimately traced the original Homo sapiens back to the African shore, from which they began their remarkably rapid colonization of the world, as much alongshore as inland.

Ironically, it was when nations turned away from the sea as a place of work that writers and painters turned their full attention to the sea itself. They turned it, as never before, into a place of spiritual and physical recreation. In what Margaret Cohen has called the “sublimation of the sea,” they gave it new cultural status, a higher aesthetic power. The ocean became a fountain of images and metaphors— the shipwreck being only the most prominent—that have continued to influence western culture to the present day.

Even as the numbers of those who went to sea for a living diminished dramatically, Thomas Cole’s famous 1842 four-part painting The Voyage of Life captured popular imagination, with more and more people describing their lives in nautical terms. As one student of this extraordinary turn of events puts it, “human beings living on land nevertheless prefer, in their imagination, to represent their overall condition in the world in terms of a sea voyage.” Pristine nature, now in short supply in industrialized heartlands, found refuge in the oceans, while the mystery once associated with terra incognita relocated to the deeps. Simultaneously, the sublime, previously associated with mountains and forests, came to be associated with wild water.

It was in the era of the thoroughly landlocked industrial revolution that the sea first became a part of mainstream mainland culture. Even as the numbers of Americans earning a living from the sea declined sharply, the middle classes took on what Henry David Thoreau called the “marine tint.” To some young American men like author Richard Henry Dana, a few years before the mast became a rite of passage. A passion for yachting developed on both sides of the Atlantic in the later nineteenth century, and, by the early twentieth century, swimming had become very popular. In the course of the next hundred years, millions of Dana’s countrymen, who had originally arrived by sea, would return to it, this time for a variety of aquatic activities that had not even existed earlier.

But even those who never crossed the tide line embraced maritime figures of speech and made the sea a metaphor for life on land. With their children in sailor suits, middle-class parents began to colonize the shore for fun as well as health, filling their urban and suburban homes with aquariums and seascapes. As one historian puts it, “During the nineteenth century . . . the ocean entered the minds, homes, dreams, and conversations of ordinary people.” It did so through the art of seascape, adventure literature, and, in a much more mundane way, in the collections of tropical fish, seashells, corals, and scrimshaw. “Often it seems that the more people become urbanized,” writes Paterson-Hamilton, “the more they want about them talismans of nature on their walls, their shelves, their keyrings.”

Beginning in the late eighteenth century, people began to come back to the sea in search for a quality they felt to be missing in the new industrial environment, that something called wilderness. The desire for an experience of untamed nature originated in the eighteenth century among a small group of European aesthetes, for whom the awesome power of the sea, as witnessed from the safety of land, was a powerful emotional and mental stimulant. The terror and awe that religious folk had previously associated with the supernatural was now relocated to nature itself. In 1712, Joseph Addison wrote of the “agreeable Horrour ” evoked by tempests: “Of all Objects that I have ever seen, there is none which affects imagination so much as the Sea or Ocean.” Edmund Burke also preferred the sea to the land as a tonic for mind and soul. No one knew this better than Jules Verne, who wrote: “The human mind delights in grand visions of supernatural beings. And the sea is their very best medium, the only environment in which such giants . . . can be produced and developed.”

Dreams and nightmares that had previously been projected on terrestrial landscapes were now invested in seascapes. Even as the oceans became an object of science, they produced new myths. The notion of Atlantis, the submerged continent, was revived by a modern world anxious about its own survival. The sea gravitated to the center of western collective consciousness. The contemporary writer Jonathan Raban has called it the most protean of all symbols because it is “not a verifiable object . . . it is, rather, the supremely liquid and volatile element, shaping itself newly for every writer and every generation.” It became a symbol of eternity, a comfort to those who, having lost their faith in divine dispensation of everlasting life, came to see in its apparently timeless flows evidence of nature’s immortality and a secular promise of life everlasting. For Joseph Conrad, who despised what had happened to land in the industrial age, the sea was the only viable alternative.

The sea became a mirror that landlubbers used to reflect on their own condition. Even as actual involvement with the sea diminished, its symbolic and metaphorical presence increased. “We have a fine sea,” declared Charles Dickens, “wholesome for all people; profitable for the body, profitable for the mind.” In America as well, there developed what was “essentially a coastal, sea-consciousness culture with a developing literary tradition anchored in romantic impulses.”

But the sea also operated on a more personal level, as a metaphor for life. In an era when everything seemed to be in a state of becoming, it represented the flow of life in ways that the land could not. “Here,” wrote J. G. Francis of the seaside, “better, we think, than in any inland scenery, man can muse and meditate.” The flood tide was a reminder of childhood and youth, the ebb tide old age, while the horizon “tells of a steadfast future, an immutable eternity.”

We have come to know the sea as much through the humanities as through science. Most of our encounters with it are at a distance, by way of the illustrations and stories of our childhoods. Rachel Carson was smitten early with images of the sea, but did not really become acquainted with it until adulthood, though she never really learned to swim. Often it is an iconic seascape or photograph that lures us to a particular shore. The sea lurks in the imaginations of millions, if not billions, of people who will never test its waters. It is forever in our dreams and nightmares, more now than at any time in history. The manner in which this occurred and the significance it holds for modern culture and society is only just beginning to dawn on us. This is the domain of the blue humanities, open, like the sea itself, to further exploration.