He insisted his greatest book wasn't Huckleberry Finn but rather Personal Recollections of Joan of Arc:
Throughout her short life, Joan of Arc maintained the sort of traditional values that can make social change infinitely more palatable. She was strong. She was a legendary leader. She was an unrepentant and proud soldier. But to Twain at least, she also represented something decidedly feminine: she was a virgin; she was pure of tongue; she was respectful and unassuming. … In this way, Joan somehow miraculously fulfilled the two parts of Twain's ideal of womanhood—she was an intellectual equal but a modest and self-abnegating one. She represented both his love for traditional girlishness and the aspirational benchmark he set for the generation of intrepid young girls he imagined were about to come of age.
The Dish 