These letters were arranged in two volumes by Albert Bigelow Paine, Samuel L. Clemens's literary executor, as a supplement to Mark Twain, A Biography, which Paine wrote. They are, for the most part, every letter written by Clemens known to exist at the time of their publication in 1917. They begin with a fragment of a letter from teenaged Sam Clemens to his sister, Pamela, and conclude with a letter to his attorney two weeks before his death.