Thoreau is a writer of biography, essayist, and a poet. He is also a philosopher in the informal sense. His chief works are College Essays, The Service, The Natural History of Massachusetts, A Walk to Wachusett, The Landlord, A Winter Walk, Thomas Carlyle and His Works, Slavery in Massachusetts, Walden, A Plea for Captain John Brown and Other Brown Essays, The Succession of Forest Trees, Autumnal Tints, Wild Apples, Life Without Principle, Walking, Poems, Excursions, The Maine Woods, Cape Cod, A Yankee in Canada, Journal. He also wrote poems. Nevertheless, his most important prose works are Walden, The Week, and his writings in the Dial, a journal of the transcendentalists.

Thoreau was a disciple of Emerson in following Transcendentalism. He maintained an intimate and sympathetic relation to the Transcendental Club, to the leading Transcendentalists as individuals, and to the Dial, their periodical. Transcendentalism referred to the self-sufficiency of the human mind, the creative powers of man. It spoke for an order of truth that transcended by immediate perception, all external evidence. Thoreau believed in all this and saw the manifestation of God in Nature. He recommended a life close to nature full of economy and simplicity. Thoreau himself wrote in his Journal in 1853, “I am a mystic, a transcendentalist, and a natural philosopher to boot.” In a letter to Charles C. Morse he wrote: “I am in the lecture field, but my subjects are not scientific, rather Transcendental and aesthetic.” It was as a transcendentalist that he laid stress upon solitary communion with the infinite and believed a thing right if his intuition said that was right. The best examples of his Transcendentalism are found in the contribution to The Dial. To him Nature was the best resort. Nature pulsates with life. He believed that man flows unto God when the channel of purity is open.

Thoreau was a critic of a society. He was a rebel. He discarded American materialism and slavery in some of America’s districts. In his Slavery in Massachusetts he launched two fronted attack against the conventional mode of living: (1) reform the individual, and (2) destroy the corrupting institutions. Thoreau attacks herein both the press and the church as defenders of slavery. In Walden, he recommended the life of quiet desperation which most men lead; the economic fallacy which is responsible for the situation in which they find themselves; the meaning of life close to nature and its rewards; the higher laws so essential for a spiritual living.

Thoreau also attacked contemporary fashions and clothes and the ways of living of the Americans. He advised them to be simple and economic, pure in behaviour, word, thinking and action.

Thoreau was an ideal hermit; Emerson called him a “stoic and hermit.” R.L. Stevenson called him a “stalker” because he shirked his social responsibilities and retreated to Walden Pond, a lonely place to live in. But he did not hate mankind of human life ; he did no seek an escape from it. He was an ideal hermit devoted to his work. His civil Disobedience was a Mahatma’s call to another Mahatma (Gandhi). He liked simplicity, economy, truth, purity of living and thinking, austerity, sincerity, servity, and calm of mind and peace of environment. All these are the characteristics of a hermit. He advocated fair means for fair ends. He was a truth-seeker. He was a practical idealist.

Thoreau was a prophet of nature; he was its lover and worshipper. He loved the hills and rocks, the rivers and ponds, the trees, plants and flowers, the animals and birds, the greenery and the forest, the fauna and flora. He recommended a life very close to nature. He was a nature-poet and a poet-naturalist.

Thoreau’s total work consists of twenty volumes, including his letters, speeches, essays, poems, and journals. This includes his best works Walden and The Week. He has been variously called as a poet naturalist, a Transcendentalist, a cosmic Yankee, a bachelor of Nature, and a social rebel. He is not all these separately, but all in one. He is indeed a challenge to the so-called sophisticated man.

Thoreau lacked a sense of humor. Lowell also charges him somewhat fairly, that Thoreau lacked the capacity for organization. Walden is his masterpiece in mosaic. It is the game of his great care, artistry, finish and economy of language. Since he was engaged in writing autobiographical narrative, he could not be extremely organizational. Yet he is not always haphazard.

As a prose writer Thoreau employed analogies in abundant and recommended their use to those beginning the study of the art of writing. He was, beyond doubt, guilty of chronic exaggeration, knew it himself, and sometimes defended it, as where he maintained that poetry is only an exaggeration of history. Later on he abandoned this concept. In matters of style and ideas Carlyle’s influence is profound. Both used highly conventional expressions. While describing Nature, Thoreau’s prose becomes delicate, simple yet eloquent, colloquial austere. His style has been praised for its simplicity too. His writing is rich in similes and metaphors. What Thoreau said of Carlyle could be said for his own work too. Speaking about Carlyle’s books Thoreau said: “they are… works of art only as the plough. And corn mill and stream engine not as pictures and statues.” In part his writing is reminiscent of the pamphleteering prose. He had a passion for terse and compact sentences. His style is also remarkable for clarity, for descriptive ability, his command of epigram, his use of symbolic analogy and his sense of language.”

As a poet he loved Homer, Ossian, Chaucer and Wordsworth. He said that the best poetry is not counted on the poet’s fingers but on his heart strings. “A true poem is distinguished not so much by a felicious expression, or any, thought it suggests, as by the atmosphere which surrounds it.” According to Brooks and Bettmann, “His poems were of a homespun kind, well woven, but indifferently out. The smoke obscured the flame, but now and then a jet rose out of the smoke, and Henry wrote a line or two that shivered its way up the spinal marrow. If his poems were often disjointed, like his prose, it was because of his habit of journalizing. He jotted down his paragraphs and verses and waited for a cooler moment to patch them together-a good way for epigrams, but fatal for poetry, and none too good for prose.”

Writing about his journal Brooks and Bettmann say, “His journal was a calendar of the ebbs and flows of the soul. It was a beach on which the waves might cast their pearls and seaweed.” What is true of Journal is true of this whole writing.

He believed in the sincerity of writing. To him “An honest book is the noblest work of man.” He liked biographies and travels most. His books are wildly natural and primitive, mysterious and marvelous, ambrosial and fertile, as a fungus or lichen. He is cool and calm. He cannot inflame the minds of this audience. According to him, the writer is a prophet. Lowell, rightly or wrongly, interprets Thoreau as a romanticist. In the words of Ludwig Lewisohn. “He has something of their (Greeks)limpidness, severity, colour of dawn and dusk… He is, as a mere writer, the soundest as model and influence among American men of letters” Alone with the help of his Walden, he has been put on the shelf of classics.

There are oriental echoes as they are in Emerson and Whitman. His response to Indian Philosophy is intellectual. He called himself ‘a Yogi’. He learnt oriental literature through French and English sources. He compares the Hindu scriptures with the Bible and Christ with Buddha in A Week. Of all the Hindu scriptures, the Bhagavad-Gita wielded the most potent influence upon him. He calls it ‘one of the noblest and most sacred scriptures which have come down to us.” He calls it “the New Testament”: he loves its sanity and sublimity and its stupendous and cosmogonal philosophy.

Lowell calls Thoreau merely a copy of Emerson. Stevenson called him “a stalker,” a man possessed of negative virtues, who had no courage to face the hazards of life. No doubt he was an observer and a natural historian, industrious and persistent, yet, to quote John Burroughs, “He has added no new line or touch to the portrait of bird or beast that I can recall…. To the last his ornithology was not quite sure not quite trustworthy.” L Powell has said that Thoreau’s passion of Nature is not consuming, that he has no sense for style, and that his personally was under developed resulting in the suppression of this normal emotions. So he concluded that Thoreau is “neither a profound thinker nor a great writer.”

Thoreau’s admires are of a different opinion. Canby calls him "a great writer as well as a great man" ; "one of the masters of English prose, purer, stronger, racier, closer to a genuine life, rhythm, than any of his contemporaries in England or America.” And to quote Walter Blair & others: “The growth of Thoreau’s frame in the third and fourth decades of the present century has no doubt been owing not only to a recognition of his fine literary qualities but also to various special appeals which his works make to modern readers. His lessons in simplicity and economy have appealed to those who are harassed by the complexity and expense of modern life. His almost primitive intimacy with nature has come home to a generation whose mode of life is largely artificial and divorced from natural influences. His sturdy, rebellious increasingly regimented society. His indigenousness, deeply rooted in a particular place, has been warning and a rebuke to a generation so mobile and migratory that many people can scarcely be said to have roots everywhere. In short, we read Thoreau for those values which we have lost and which more and more seem necessary to our health and vigor and peace of mind."