Uncle Tom's Cabin is no piece of evidence or historical artifact. If all slave owners were typical of Simon Legree, slavery would not be profitable since most of the slaves would be incapable of working after such horrible beatings. Rather, it was written more as propaganda by Harriet Beecher Stowe, an active abolitionist, exciting people against slavery with the heinous character of Simon Legree. Much like Upton Sinclair's The Jungle, its intent was to reform conditions. And, it did. Uncle Tom's Cabin is credited with helping to fuel the abolitionist cause of the 1850s.
Note also how "Uncle Tom" is used today as an insult and racial slur. I think that many people using it have no memory of what the phrase actually means or how it was used or even the character it is based on. We need the book not only as a cultural artifact (regardless of modern relevance) but as a reminder that words have meaning, and to use them without knowledge is as bad as suppressing them altogether.
To me the book seems more important as a barometer of the time, much like Upton Sinclair's The Jungle, than as a singularly important piece of literature. It shows the polarization of the 1850s in America and arguably had an influence on the foreign policy of England during the Civil War, but is less impotant today as literature. My humble opinion of course.
I must agree with some of the others posters when examining the novel's relevance today. The novel does offer a window into the past. Readers can examine the treatment of people as it has been in the past and how society reacted to racism. The novel provides a very "open window" to what has happened in America's history.
One relevance of the novel is how it is an historical testament to the power of creative literature on humanity. Maybe it didn't start the Civil War, but it was certainly a work which put a human face on slavery and affected many of its readers with an increase in their opposition to the institution. One book had the power to get people talking, and that talk eventually turned to action. Stowe had a social agenda, but the book probably superseded her intentions. It is also relevant in that while slavery is gone, race relations in this country are still a hot button issue.
I'll take a formalist approach and say that the book is still relevant today if it is well written and skillfully designed and functions as a powerful example of what can be done with the English language. In these senses, great works of literature never go out of date. Whether Stowe's novel is a great work of literature in these senses is open to debate, and in fact I would be very interested in reading an article or book that made the case for Stowe's novel on artistic grounds alone. Does anyone know of such a case being made for this novel?
The book remains relevant as an historical document. I believe Lincoln, when he met Stowe, called her the little lady who started the Civil War. Here is a fairly full discussion of that alleged statement: http://wraabe.wordpress.com/2008/06/26/abraham-lincoln-to-harriet-beecher-stowe-the-author-of-this-great-war/
I agree that it is only really relevant today as a window on the past. The book, outside of its historical context, is no tremendously important piece of literature. It does not illuminate the human condition as well as other works that are classics in their own right. Therefore, the main value of this book today is as a piece of evidence that tells us something about what the US was like 150 years ago.
This is not an easy question to answer, because interpretations on Uncle Tom's Cabin are mixed. For example, is uncle Tom to be emulated as a man of Christian character, or rejected as a weak subservient man, who kowtows to authority? Or are there other interpretations? With that said, I think this book is not only worth reading, but also very relevant to today in many ways. Let me offer a few points.
First, no matter what your view is on the book, the goodness of the protagonist cannot be in doubt. Tom's goodness shines through. This, I think, is strength of character. Moreover, it is people like this, who do good even to wrong doers, that shows injustice for what it is. It is a form of Christian non-violence and when it is done consistently, it could bring about a revolution. Martin Luther King showed us this. In a world at the brink of war, we should seriously consider this message.
Second, the book is relevant today, because it deals with race and the power imbalances based on race. What should we do with the imbalances of everything out there?