Från IMDB:
Instead of coming in from the Cold War, British agent Alec Leamas chooses to face another mission.

The acclaimed, best-selling novel by John le Carré, about a Cold War spy on one final dangerous mission in East Germany, is transmuted by director Martin Ritt (Hud, Norma Rae) into a film every bit as precise and ruthless as the book. 

Academy Award-nominated Richard Burton (Who's Afraid of Virginia Woolf, Becket,1984) is superb as Alec Leamas, whose relationship with the beautiful librarian Nan, played by Claire Bloom (Hamlet, A Streetcar Named Desire), puts his assignment in jeopardy.

Winner of 4 BAFTA Awards (including Best British Film) The Spy Who Came in from the Cold is a hard-edged and tragic thriller, suffused with the political and social consciousness that defined Ritt's career. The Masters of Cinema Series is proud to present the film on Blu-ray for the first time in the UK.