Wittgenstein was unique amongst 20th century philosophers in that he precipitated two revolutions of thought despite only have one publication during his lifetime. The first was his enormous influence on logical positivism and the second was his possible repudiation of it in later work. However, a much-neglected aspect of W-scholarship is his relationship to Christian belief despite his encounter with Tolstoy’s synthetic Gospel  which exerted a life-changing influence on him. During WWI Wittgenstein had acquired Tolstoy’s redaction of the gospels and carried it with him during the war and during his internment (in addition to the Tractatus that he managed to finish at that time). He did not carry any other material or books with him. By considering the Tractatus in this context, we can understand it far better.
It is one of the vexed questions of Wittgensteinian scholarship as to whether the logical positivists had fundamentally misinterpreted his Tractatus. He wrote to his close friend Paul Engelmann that Bertrand Russell had completely misunderstood it, but he allowed the introduction to remain because it ensured publication with Russell’s seeming endorsement. Without it, the publisher would not publish. Engelmann’s memoir (1967) is one of the most illuminating as it covers the period around the preparation and publication of the Tractatus, providing some interesting insights into what was in the mind of Wittgenstein in writing it and most significantly what was not, the latter arguably being the positivist use and interpretation of it which Wittgenstein himself came to emphatically reject, though it would be disingenuous to assert the positivists did not exert some reciprocal influence on Wittgenstein during that early period.
However, it remains of great debate whether the “mid-Wittgenstein”  and the “late-Wittgenstein”  (again, contentious categories within Wittgensteinian scholarship) were contiguous in an important sense with his early work or were a radical departure. He certainly reflected in later life that he had placed too much importance on the “language game of science” at the expense of other uses of language, what came to be called “ordinary language philosophy” at Oxford University (though Wittgenstein himself was attached to Cambridge). Wittgenstein had periods where he did work closely with both Schlick and Carnap and his Tractatus had exerted an enormous influence on the Vienna Circle. The opaqueness of the relationship with the positivists is enlightened somewhat in that the positivists, like Russell before them, had failed to grasp the place Wittgenstein had granted the “mystical” that “can only become manifest but never be communicated in explicit statements”.
Thus, his mysticism and spirituality were what set him apart from other key personalities within the Circle and the argument of the Tractatus might be interpreted as ‘ringfencing’ the supremely significant but inexpressible in human language, making it immutable and immune to criticism in human language. This interpretation seems diametrically opposed to the verificationist view that characterised the positivists, and the problem remains that the verificationist principle was originally known as Wittgenstein’s Verification principle before he publicly distanced himself from the scientism of logical positivism. However, by appreciating his mysticism, perhaps reflected also as his work as a gardener in a monastery after his first retirement from philosophy, we get a far better feel for his motivation.
 Tolstoy, L. (1997 (c1902)). The Gospel In Brief (Bison Books ed.). (F. Flowers III, Ed., & I. Hapgood, Trans.) Lincoln (NE): University of Nebraska Press. The editor’s preface describes the dramatic effect this book had on Wittgenstein.
 Monk, R. (1991). Ludwig Wittgenstein – The Duty of Genius. London: Vintage., pp. 281-308. For example, Carnap had been “very excited” after speaking to Wittgenstein.
 This would be the period of the Blue and the Brown books, which were research for the “Philosophical Investigations”. However, other works primarily created from the notes of his students do exist from that period on subjects as diverse as Mathematics, Culture and Value, and Religious Belief.
 The main work from that period is “On Certainty” which is sometimes thought of as a reflection on G E Moore’s defence of common-sense realism. Although there was some tension between them at different times, G E Moore was influential in persuading Wittgenstein to return to philosophy after visiting him in Norway.
 Ignoring the complexity of Russell’s relationship with the Vienna Circle of which he was certainly a close kindred spirit who attended inter-war meetings of the Circle. The Circle eventually disbanded because of the changes in Austria and Germany with many of the key personalities finding their way to academic positions in the premier Ivy League universities in the US or at the equivalent establishments like Oxford, Cambridge and UCL in the UK.
 Josef Schlächter in the Preface to Engelmann’s memoir (1968).
 During the same period, he also worked as an elementary school teacher and designed a house for one of his sisters in Vienna. He might be described as having a “second” retirement from philosophy during the 2nd World War where he sought for more “meaningful” work. J C Ryle helped him find employment first as a porter at Guy’s Hospital and then with a medical lab. However, he returned to Cambridge 1945-7, visited Norman Malcolm at Cornell and stayed philosophically engaged until his passing in 1951 at the age of 64.