What lesson can be learned in Uncle Tom's Cabin by Harriet Beecher Stowe?

The overarching lesson Stowe wanted to convey in her novel is that even under the best of conditions, slavery was an evil institution. People in her time often justified slavery with the argument that while some owners mistreated their slaves, most were good-hearted and cared for their slaves well. Stowe opens the novel with a depiction of the Shelby family in Kentucky, who are, indeed, good slave owners. Nevertheless, Stowe wants readers to understand that even in the best of situations, slavery is a terrible condition in which to live. Once Mr. Shelby finds himself in financial trouble, he sells his slave Uncle Tom to settle his debts: this shows that any slave, at any time, no matter how good (and Uncle Tom is the best of human beings) could be separated from his wife and children and have no recourse. Uncle Tom eventually dies at the hands of a sociopathic owner. Stowe wants us to take away the lessons that slavery is a cruel, dehumanizing institution, slaves are human beings, and all humans should be treated with decency.