In his lecture, Alberto Manguel considers the implications of the eighteenth-century work of Raimondo di Sangro, Prince of Sansevero, on a curious system of communication employed by the Incas consisting of rows of colored knots. Raimondo di Sangro was an eccentric inventor, printer, and visionary who imagined a method for deciphering this language and opened questions about the use of memory and the transmission of meaning.