Walter Harding, "Thoreau, Henry David," American National Biography Online, February 2000, http://www.anb.org/articles/16/16-01635.html.
The popular image of Thoreau as cold and negative was created in large part by his friend Emerson, who saw Thoreau as stoic and therefore overemphasized these qualities in both his eulogy and in his subsequent editing of Thoreau's letters. There is no question that Thoreau could at times be crusty, abrupt, and cantankerous. His friend Caroline Sturgis Tappan once said that he "imitates porcupines successfully." He loved to deflate the pompous and disturb the conservative. But on the other hand, he was a loving son and a thoughtful brother. The Emerson children adored him, as did most Concord children, who loved to hold his hand during walks, visited him at his Walden cabin, brought him natural history specimens for his collections, and plied him with questions because he was one of the few adults who would try to answer them. He also regularly risked arrest to assist escaping slaves on their way to freedom. Despite Thoreau's occasional grumpiness, he was, as Henry Canby has suggested, the happiest of all the Concord writers.