In his devotion to peace, Tagore denounced nationalism and violence. He sought to instill in human beings a sense of their unity; he was severely critical of the Indian caste system. His most important philosophical work is Sadhana: The Realization of Life (1913), which echoes the fundamental ideas inherent in sacred Hindu writings. His dramas are filled with lyricism and philosophy, while his poems deal with amorous, mystical, and fabulous themes. In India his appeal was nearly universal. A man of striking appearance, Tagore came to be regarded with the reverence due an ancient teacher. He wrote in Bengali but translated much of his work into English. It attracted attention in the West, and he was awarded the 1913 Nobel Prize in Literature, especially for his collection of poetry, Gitanjali (1912). His Janaganamana (Thou Art the Ruler of All Minds) was adopted as the Indian national anthem.

Tagore's best-known novels and poetry include The Gardener (1913), The Crescent Moon (1913), Songs of Kabir (1915), Cycle of Spring (1917), Fireflies (1928), and Sheaves (1932). Among his plays are The Post Office (1914), Chitra (1917), and Red Oleanders (1924). Philosophical works include Personality (1917), Nationalism (1917), The Home and the World (1919), The Religion of Man (1931), and Man (1932). In 1915 Tagore was knighted. His travels and lectures took him around the world. He was impressed with the capacity of the West for accomplishing its practical goals, but he deprecated what he considered its spiritual emptiness and waste. In 1922, Santiniketan (abode of peace), the school he had founded at Bolpur in 1901, was expanded into the internationally attended Visva-Bharati Univ. The curriculum stressed social reform, international unity, and rural reconstruction.