He published his first book Modern Painters in 1843, under the anonymous identity "An Oxford Graduate". It argued that modern romantic landscape painters — in particular J.M.W. Turner — were superior to the so-called "Old Masters" of the Renaissance. Such a claim was highly controversial, especially as Turner's semi-abstract late works were then being denounced as 'meaningless daubs'. Ruskin argued that these works derived from Turner's profound understanding of nature. He soon met and befriended Turner, eventually becoming one of the executors of his will.

   Ruskin followed this book with a second volume, developing his ideas about symbolism in art. He then turned to architecture, writing The Seven Lamps of Architecture and The Stones of Venice, both of which argued that architecture cannot be separated from morality, and that the "Decorated Gothic" style was the highest form of architecture yet achieved. By this time Ruskin was writing in his own name, and had become the most famous cultural theorist of his day.

   In 1848, he married Effie Gray, for whom he wrote the early fantasy novel The King of the Golden River. Their marriage was notoriously unhappy, eventually being annulled in 1854. Effie later married the artist John Everett Millais, who had been Ruskin's protegé.

   The Pre-Raphaelites were influenced by Ruskin's theories. As a result, the critic wrote letters to The Times defending their work, later meeting them. Other artists influenced by the Pre-Raphaelites also received both written and financal support from him, including John Brett, Burne-Jones and John William Inchbold.

   Upon the death of his father, Ruskin declared that it was not possible to be a rich socialist and gave away most of his inheritance. He founded the charity known as the Guild of St George in the 1870s and endowed it with large sums of money as well as a remarkable collection of art. He also gave the money to enable Octavia Hill to begin her practical campaign of housing reform. He also taught at the Working Men's College, London and was the first Slade Professor of Fine Art at Oxford, from 1869 to 1879, he also served a second term. Ruskin College, Oxford is named after him.

   While at Oxford Ruskin became friendly with Lewis Carroll, another don, and was photographed by him. After the parting of Carroll and Alice Liddell, she and her sisters pursued a similar relationship with Ruskin, as detailed in Ruskin's autobiography Praeterita.

   During this period Ruskin fell deeply in love with Rose la Touche, an intensely religious young girl. He met her in 1858, when she was ten years old, proposed to her eight years later, and was finally rejected in 1872. She died shortly afterwards. These events plunged Ruskin into despair and led to bouts of mental illness. In later life he suffered from a number of breakdowns as well as delirious visions, and took up forms of utopian spiritualism.

   The emergence of Impressionism in painting alienated Ruskin from the art world, and his later writings were increasingly seen as irrelevant to contemporary art, especially as he seemed to be more interested in fantasy book illustators such as Kate Greenaway than in modern art. Much of his later life was spent at a house called Brantwood, on the shores of Coniston Water located in the Lake District of England, amid intermittent bouts of madness.

Further reading:

 Wolfgang Kemp. The Desire of My Eyes (1990)
 Guy Davenport. "Ruskin" (essay)