This volume covers the origin, interpretations, and reception of Wittgensteins Tractatus Logico-Philosophicus and offers a critical assessment of the related research and contemporary historiography. The authors deal with an evaluation of research on Wittgensteins philosophy, life, and work, as well as of the editions of his work published since his death. This includes upcoming editions with a special focus on the availability of Wittgensteins (digital) Nachlass. Special attention is given to the reception of and references to the Tractatus in the middle and later Wittgenstein, as well as the reception by other philosophers. Moreover, open philosophical, ethical, and (unresolved) scientific questions are addressed with a critical investigation of current research. Furthermore, the complex, diverse, and mutual relation of Wittgenstein and the Vienna Circle of Moritz Schlick, Otto Neurath, Friedrich Waismann and others are addressed.