Introduction by Bertrand Russell. First English edition, third impression 8vo; original cloth boards. This work is acclaimed the most important book of twentieth-century philosophy. It is printed in English with facing text in German. With the bookplate of H.A.R Philby to the front pastedown. Harold Adrian Russell Philby (1912-88), Intelligence officer and spy - "Kim" Philby. The front free endpaper is inscribed in an unidentified hand, "March 1948. You have quoted this to me so often (p.189), that I thought it might be good for you to go so far as to read the book. Dear. [Monogram]. 1948. P.S. What he says is true, in the deepest sense, but makes life impossible, in the deepest sense. P.P.S. How deep is your sense? [Monogram]." On p.189 the same writer has bracketed proposition 6.54 and added the word, "Mercy!", and then underlined the final proposition, presumably the one referred to in the main inscription and arguably Wittgenstein's most famous epigram ("Whereof one cannot speak, thereof one must be silent"), and added beneath it, "Which Brindle thinks is terribly old-fashioned, Christian, & dull, & somehow rather vulgar, too.[Monogram]." At the time of its inscription, Philby was working as head of British Intelligence in Istanbul and was almost certainly having an affair with Edith Whitfield his secretary, who also happened to be a friend of Guy Burgess. Near fine.