The author, John Ruskin (1819 – 1900) was the leading English art critic of the Victorian era, also an art patron, draughtsman, watercolorist, a prominent social thinker and philanthropist.
Ruskin first came to widespread attention with this work, an extended essay in defence of the work of J. M. W. Turner in which he argued that the principal role of the artist is "truth to nature". In it, he controversially argued that modern landscape painters—and in particular Turner—were superior to the so-called "Old Masters" of the post-Renaissance period. He maintained that the job of the artist is to observe the reality of nature and not to invent it in a studio—to render what he has seen and understood imaginatively on canvas, free of any rules of composition.
http://en.wikipedia.org/wiki/John_Ruskin
1st American from the 3rd London ed. / revised by the author