One of the most steadfast and famous abolitionists in New England, he was far more radical than William Lloyd Garrison, if, that is, radicalism is measured by a willingness to entertain violence for the social good.

NPR: Excerpt: 'White Heat'

The collection includes letters from David Lloyd George, William Gladstone, Rudyard Kipling, George Bernard Shaw and Arthur Conan Doyle.

BBC: Alfred Russel Wallace's 19th Century letters go online

David Lloyd George, William Gladstone, Rudyard Kipling, George Bernard Shaw, Arthur Conan Doyle and Darwin himself are on the list.

BBC: Search for Alfred Russel Wallace's 19th Century letters