Tomas Alfredson’s Tinker Tailor Soldier Spy, adapted from John Le Carre’s novel, may not be snowbound like his Let the Right One In, but it’s nearly as chilly, and it may well be just as good in its own right. Three things need to be understood before undertaking this film. First of all, this is not an action thriller. Its thrills are more cerebral in nature. Second, this is not a film for people who aren’t prepared to actually pay attention to what they’re watching and to what they’re hearing. Third, this isn’t a version of the book that tries to slavishly reproduce every page of the it; you’ll find something more like that with the 1979 seven-part BBC series. As self-contained work, this, however, is the goods. It’s a Cold War era story set in 1973 that finds the head of MI6 — known as Control (John Hurt) — convinced that there is a Russian mole “right at the top of the Circus.” But before he can get very far in his investigations, an espionage bid goes wrong and both Control and his right-hand man George Smiley (Gary Oldman) are put out to pasture. Soon, however, Control is dead and Smiley has been called out of “retirement” to learn the identity of the mole. Much of the film depends on the performances of its handpicked cast: Colin Firth, Toby Jones, Ciaran Hind, Mark Strong, Benedict Cumberbatch, Tom Hardy, John Hurt, and Gary Oldman. The film’s Cold War setting is part of what makes it work (just as the lack of that setting is part of what feels slightly bogus about the more recent James Bond movies). It inescapably and profitably recalls the more intelligent 1960s spy films, but Alfredson’s eschews even the marginal heroics and big set-pieces of those movies in favor of an utterly matter-of-fact reality, which, in turn, makes the proceedings unsettling — to the point of nightmarish on occasion.