While overseas, Brown published a novel, Clotel: or, The President's Daughter — today considered the first novel by an African-American (though some historians question the validity of that title, considering it was published in England). It was published in three more versions over the next fifteen years (an unauthorized version also appeared in Dutch). If that's not impressive, he also published The Escape; or, A Leap for Freedom, the first play by an African-American.
Born into slavery in Kentucky (the illegitimate son of the cousin of his white owner; people later remarked on his light skin), he was kept illiterate by his several owners as he was bounced from plantation to plantation. He finally escaped to Ohio at 19 or 20 years old. He later moved to Buffalo and assisted the Underground Railroad by bringing escaped slaves across Lake Erie to Canada. He began writing for journalistic presses, becoming one of the most widely-published African-American writers of the century. He jumped genres, from autobiography to fiction to drama to poetry to history.
Once he realized he had strong rhetorical abilities, he began lecturing. His aforementioned trip to England lasted five years. The book he published on that trip, Clotel, focuses on a mulatto slave, the fictional illegitimate child of Thomas Jefferson. After escaping from bondage, her slave-masters come searching for her but she chooses to take her own life rather than return to slavery (he wrote: "Joy! the hunted slave is free!"). The novel begins with a clear statement:
With the growing population of slaves in the Southern States of America, there is a fearful increase of half whites, most of whose fathers are slaveowners, and their mothers slaves. Society does not frown upon the man who sits with his mulatto child upon his knee, whilst its mother stands a slave behind his chair.
*Much of the information from this post was gleaned from William Wells Brown: A Reader, edited by Ezra Greenspan.