Charles Sanders Peirce (1839–1914), American Scientist, Mathematician, and Logician, developed much of the logic widely used today. Using copies of his unpublished manuscripts, this book provides a comprehensive collection of Peirce’s writings on Phaneroscopy and the outlines of his project to develop a Science of Reasoning. The collection is focused on three main fields: Phaneroscopy, the science of observation, Semeiotic, the science of sign relations, and Logic, the science of inferences. Peirce understands all thought to be mediated in and through signs and its essence to be diagrammatic. The book serves as a timely contribution for the introduction of Peirce’s Phaneroscopy to the emerging research field of Image Sciences.