By the late nineteenth century, the work of naturalists John Burroughs and John Muir — both influenced by Thoreau — drew attention to Thoreau as a nature writer. Beginning in 1899, photographer and environmentalist Herbert Wendell Gleason worked to popularize Thoreau by capturing images of the places that Thoreau had known and about which he had written. Gleason's photographs of Thoreau's world were used to illustrate the 1906 editions of Thoreau's collected writings; some of them appeared in National Geographic. Gleason also presented slide lectures on Thoreau for general audiences. From the late 1960s, the rise of environmentalism focused interest not only on Thoreau's writings but also on the work of Burroughs, Muir, and Gleason. Naturalist and Pulitzer Prize-winning author Edwin Way Teale helped to popularize Thoreau in the twentieth century.
The publication of Thoreau biographies began during the decade following the author's death and demonstrated growing interest in the man as well as his work. Ellery Channing's Thoreau: The Poet-Naturalist appeared in 1873 and was reprinted in 1902. Thoreau: His Life and Aims, by H.A. Page (a pseudonym for A.H. Japp) was published in London in 1877. Sanborn's Henry D. Thoreau appeared in 1882, The Personality of Thoreau in 1901, and The Life of Henry David Thoreau in 1917. The Life of Henry David Thoreau by British biographer Henry S. Salt was first published in 1890. (Thoreau's nineteenth century British following was reflected in the publication of Walden in England in 1886 and of A Week on the Concord and Merrimack Rivers in 1889. His late nineteenth and early twentieth century recognition in England was promoted by the Labour Party, which found support in his social views.) Henry Seidel Canby's Thoreau (1939) was a popular success.
In the twentieth century, Thoreau's reputation — popular and academic — burgeoned. Interest in his work rose during the Great Depression of the 1930s, economic hardship made the philosophy of the simple life attractive, during the rebellion of the nonconformist "beat generation" in the 1950s, and during the social turmoil and Vietnam War protest of the late 1960s and early 1970s. During the 1930s, Thoreau also started to take on importance as a topic of academic study. The work of Raymond Adams from the 1930s and Walter Harding from the 1940s did much to enhance Thoreau's place in the study of American literature. In 1941, Harding played a key role in establishing the Thoreau Society, now affiliated with the Walden Woods Project (founded in 1990 to prevent development of the area near Walden Pond), both centered at the Thoreau Institute in Lincoln, Massachusetts. (The Society issues two periodical publications, the Thoreau Society Bulletin and The Concord Saunterer.) In 1971, the first volume of the authoritative "Princeton Edition" (now called the "Thoreau Edition") of Thoreau's collected writings appeared. The edition is ongoing today.
