Oliver Wendall Holmes had the heart of a Renaissance scholar because not only was he a writer, but he was a doctor, studied law and became a professor as well. Emerson, Longfellow and Lowell were his contemporaries. He was an extremely versatile writer. He wrote essays, poetry and novels. His topics, therefore, were as varied as the genres in which he wrote. One thing that characterized all of his writings, however, was wit and humor.
His works were often satirical in a good-natured way, and he wrote a great deal of poetry that had patriotic themes and social themes. For example, he wrote Old Ironsides about the pending destruction of the U.S.S. Constitution and the uproar over the poem convinced the Navy not to destroy the ship. He also wrote The Last Leaf about the Boston Tea Party. He was a popular poet and wrote many works to commemorate various occasions. If you do some research on him, you will find that his works include novels, poetry, travelogues, non-fiction books (his "Breakfast Table" series), and even medical journals.
See the link below here on eNotes for some biographical information.