The abolitionists had both theoretical and practical influence on the antislavery attitudes in the North. Their practical influence was seen in organized actions for freeing slaves and helping them escape to Canada. Quakers were often involved in these actions and were willing to risk their lives. The theoretical influence of abolitionists was immense. For example, Harriet Beecher Stowe, who wrote the famous novel "Uncle Tom's Cabin", profoundly influenced the popular thinking about slavery, not only in America, but throughout the world.