Percy Bysshe Shelley (4 August 1792 – 8 July 1822) is one of the major English Romantic poets and is critically regarded as among the finest lyric poets in the English language.

Shelley is famous for his association with John Keats and Lord Byron.

The novelist Mary Shelley (née Godwin) is his second wife.

He is most famous for such classic anthology verse works as "Ozymandias", Ode to the West Wind, To a Skylark, Music, When Soft Voices Die, The Cloud and The Masque of Anarchy, which are among the most popular and critically acclaimed poems in the English language.

His major works, however, are long visionary poems which include Queen Mab (later reworked as The Daemon of the World), Alastor, The Revolt of Islam, Adonaïs and the unfinished work The Triumph of Life.

The Cenci (1819) and Prometheus Unbound (1820) are dramatic plays in five and four acts respectively.

Although he has typically been figured as a "reluctant dramatist", he is passionate about the theater, and his plays continue to be performed today.

He writes the Gothic novels Zastrozzi (1810) and St. Irvyne (1811) and the short prose works "The Assassins" (1814), "The Coliseum" (1817) and "Una Favola" (1819).

In 2008, he is credited as the co-author of the novel Frankenstein (1818) in a new edition by the Bodleian Library in Oxford and Random House in the U.S. entitled The Original Frankenstein, edited by Charles E. Robinson.

Shelley's unconventional life, alongside a common perception of his thought as uncompromising idealism, combined with his strong disapproving voice, make him a marginalized figure during his life, important in a fairly small circle of admirers, and open him to criticism as well as praise afterward.

Long after Shelley's death, Mark Twain takes particular aim at Shelley in In Defense of Harriet Shelley, where he lambastes the 22-year-old Shelley for abandoning his pregnant 18-year-old wife and child to run off with the 16-year-old Mary Godwin.

Shelley never lives to see the extent of his success and influence; although some of his works ae published, they are often suppressed upon publication.

He becomes an idol of the next three or four generations of poets, including important Victorian and Pre-Raphaelite poets.

He is admired by Karl Marx, Oscar Wilde, Thomas Hardy, George Bernard Shaw, Bertrand Russell, William Butler Yeats, Upton Sinclair and Isadora Duncan.

Henry David Thoreau's civil disobedience and Mohandas Karamchand Gandhi's passive resistance are apparently influenced and inspired by Shelley's nonviolence in protest and political action, although Gandhi does not include him in his list of mentors.