An American poet, journalist, and essayist, Walt Whitman is often regarded as the father of free verse. He began writing Leaves of Grass in 1850 and self-published the first edition in 1855. A collection of poems written in free verse, the book includes some of his most refined verses which are loosely connected. When it first came out, the book received critical responses and was considered controversial for the obscene theme of sexuality. Whitman continued revising the collection, and various editions of the book were printed during his lifetime. In 1858, Whitman came up with a 47,000-word series called Manly Health and Training. A self-help guide, it was published under the pseudonym Mose Velsor. Whitman died on 26 March 1892. A great American poet, he continues to be remembered for his groundbreaking collection Leaves of Grass, and has influenced various poets of the twentieth and twenty-first century.