Mark Twain 
Mark Twain’s Letters [EPUB ebook] 

According to the foreword: 'Nowhere is the human being more truly revealed than in his letters. Not in literary letters–prepared with care, and the thought of possible publication–but in those letters wrought out of the press of circumstances, and with no idea of print in mind. A collection of such documents, written by one whose life has become of interest to mankind at large, has a value quite aside from literature, in that it reflects in some degree at least the soul of the writer. The letters of Mark Twain are peculiarly of the revealing sort. He was a man of few restraints and of no affectations. In his correspondence, as in his talk, he spoke what was in his mind, untrammeled by literary conventions.’