Wittgenstein's _Tractatus Logico-Philosophicus_, first published in 1921, has had a profound influence on modern philosophic thought. _Prototractatus_ is a facsimile reproduction of an early version of _Tractatus_, only discovered in 1965. The original text has a parallel English translation and the text is edited to indicate all relevant deviations from the final version.

Editorial preface to the fourth edition and modified translation -- The text of the Philosophische Untersuchungen -- Philosophische untersuchungen = Philosophical investigations -- Philosophie der psychologie, ein fragment = Philosophy of psychology, a fragment.

In arithmetic, if only because many of its methods and concepts originated in India, it has been the tradition to reason less strictly than in geometry, ...

§ i. After deserting for a time the old Euclidean standards of rigour, mathematics is now returning to them, and even making efforts to go beyond them. ...

Intellectual diary of a thinker of the school of Logical Positivism showing the day-by-day development of his philosophical ideas.

Anscombe guides us through the Tractatus and, thereby, Wittgenstein's early philosophy as a whole. She shows in particular how his arguments developed out of the discussions of Russell and Frege. This reprint is of the fourth, corrected edition.

Tractatus Logico-Philosophicus by Ludwig Wittgenstein: three parallel tree-structured editions. (1) Tree-structured arrangement of the German text, edited by David G. Stern, Joachim Schulte and Katia Saporiti. (2) Tree-structured arrangement of the English translation by Ogden and Ramsey, edited by David G. Stern. (3) Tree-structured arrangement of the English translation by Pears and McGuinness, edited by David G. Stern.

In this volume, Pears examines the internal organization of Wittgenstein's thought and the origins of his philosophy to provide unusually clear insight into the philosopher's ideas. Part I surveys the whole of Wittgenstein's work, while Part II details the central concepts of his early system; both reveal how the details of Wittgenstein's work fit into its general pattern.