Mark Twain....
The appearance of Mark Twain's name on this website might seem strange. After all, this is about Helen Keller, not Mark Twain. But Mark Twain was involved in Helen's life as a friend. In 1903, he wrote her a letter which explained their friendship in the first paragraph. The letter can be found here.
Calvin Coolidge
Helen Keller got the opportunity to meet Calvin Coolidge