"TO HER FAIR works did nature link," Wordsworth reminds us, "The human soul that through me ran." In kinship with nature--so close, so rich, so varied-- man has grown, finding fresh prospects, filling further dimensions of his own humanity. Yet for all its immediacy, the intimacy of man and nature has escaped the reach of history. Now Keith Thomas, a gifted and learned Oxford historian, explores it with ease, grace, and skill to offer a book alive with the color and charm of nature itself.

By unraveling changing attitudes to nature among the English between 1500 and 1800, Man and the Natural World plumbs the origins of the environmental ethic. Thomas begins when "human civilization . . . was virtually synonymous with the conquest of nature." Christianity taught the unique superiority of man over all living things. The devout Cotton Mather, Thomas tells us, grew troubled "when my natural necessities debase me into the condition of the beast" and resolved to make them opportunities for "shaping in my mind some holy, noble, divine thought." Man believed that the Creation was undertaken for his benefit. As lesser forms of life, animals and plants thrived solely to serve him. Animals, in harness, pasture, or wilderness, suffered all the casual cruelties of man's disdainful dominion. Forests and fens shrank to leave a finished landscape of fields and villages.

What Thomas calls "the modern sensibility" emerged in fits and starts over three centuries. Discoveries by naturalists piqued curiosity in other species. Experience with animals, on the farm and in the home, led men to respect, even ennoble, them. Thomas recalls Benjamin Marshall, a late 18th-century painter, who found "many a man who will pay me 50 guineas for painting his horse who thinks ten guineas too much to pay for painting his wife."

Together natural history and animal keeping contributed to what Thomas counts "one of the great revolutions in modern Western thought," as man doubted his unique superiority. One hyperbolic preacher even exclaimed that "there is no difference between the flesh of a man and the flesh of a toad." Man redefined his place in the natural order, taking the role of a steward, obliged to respect rights in other living things in return for the privilege of making use of them. By 1800 many of the most brutish blood sports were banned, and laws for the humane treatment of animals soon followed. Trees were not only planted but worshiped. And wild flowers were protected nearly as well as private gardens were tended. Where once nature was ruthlessly mastered for its economic value, it was protected and venerated for its aesthetic and moral worth.

Thomas manages his vast enterprise to a modest design. Lightly but surely, he marks the contributions of the revolution in science, voyages of discovery, revisions in theology, use of herbals, symbols of heraldry, growth of industry, styles in cookery, fashions in art, ethics of vegetarianism and other kindred subjects.

Around these themes Thomas arranges evidence so abundant, so lively, it mutes his own voice. He recalls forgotten symbols like the glow-worm shining with the light of the Holy Spirit and the mole blind as a Papist to the error of his ways. He tells of long-lost superstitions that warned against hatching plots near an eavesdropping dog-rose or protected the wren in rhyme:

Dick took a wren's nest from his cottage-side

And ere a twelve-month past his mother dy'd. There are aphorisms aplenty, and anecdotes abound. We learn of Lord Erskine, an 18th-century nobleman who kept in his bizarre menagerie a pair of leeches, each named for a well-known surgeon; of Colonel Abraham Holmes who, condemned with others to hang in 1685, marched the prisoners to the scaffold rather than have horses whipped to draw them; and that Byron loathed fishing: Whatever Izaak Walton sings or says:

The quaint, old, cruel coxcomb, in his gullet

Should have a hook, and a small trout to pull it.

Above all, this abundance of literary and anecdotal evidence indicates how deeply, how thoroughly concepts of nature color our thought and language. For the most part, Thomas approaches nature literally, but he also shows how man has read particular social conventions into the natural world and then extolled them as "natural." For example, the highly stratified, stilted society of the ancien r,egime was often likened to the natural hierarchy described by the "great chain of being." As the "modern sensibility" ripened, nature was less often invoked as a quietist apology for the status quo than as a radical critique of civil society--the stridency of Rousseau overcame the sophistry of Pangloss. Nature has undergone countless other metaphorical shifts from classical myth ology to modern sociobiology and behavioral sciences. These metaphors express what Rousseau calls "the voice of nature in us"--conscience.

Paradoxically, Thomas suggests that we turned our conscience to nature only when its conquest was nearly complete. The environmental ethic, he explains, arose with prosperity, but prosperity wrenched from nature itself. His explanation leads him to a dilemma. For man has come to look upon himself as a predator, if a remorseful one, saddled with reconciling the ascendancy over nature that civilization requires with the sensitivity to nature that civilization fosters.

Thomas uses the tools of the historian's craft expertly to explain that this dilemma is not an ephemeral issue of our times but an integral part of our humanity. He puts history to its highest purpose and achieves it in a style at once pleasing and perceptive. Man and the Natural World, like a favored guidebook, is both a reliable guide and a congenial companion.