Nowadays it seems like the "spy" genre is filled with fast paced James Bond style action. But John le Carré's novel "Tinker Tailor Soldier Spy" is quite the opposite.
After a blown spy mission behind enemy lines, major shifts in power have taken place in the British spy agencies. When vague but relevant evidence reveals that there may be a Russian mole near the top of the British secret service, retired agent George Smiley is put on the job to investigate. And as Smiley gets closer to the mole's identity, he also gets closer to figuring out what happened on that blown mission and why he was forced into retirement.
The novel's plot is delicately paced, but executed perfectly. It's slow, but it is deliberately slow. The story unwinds - going back and forth through time - until everything has been revealed. To be honest, at times it can wear on the reader's patience, but when the truth is revealed the novel is redeemed.
George Smiley - through whose eyes we see most of the novel, indirectly - is an interesting character. He has his obvious weaknesses, but a keenness with which he uses those weaknesses to his own advantage (if that can be understood and believed).
The book is weakest in terms of its length. There are many sequences in which we're provided detail after detail. Some of those details become quite important, but it's hard to parse those out as you read. Instead, there are huge monologues and flashbacks that the reader must pay attention to, even if the reader is unsure what they are paying attention for. This perspective puts the reader in almost the same position as the protagonist - trying to pull out the meaningful details from a hodgepodge of rumors and hearsay.
In fact, the process of finding out who the spy is dwarfs just about everything else, even to the point that the big reveal - when we finally find out who the Russian mole is - is almost anti-climactic. (This isn't to say that the reveal isn't important or exciting, though.)
Overall, it's an excellent novel. It is unique and well written, and definitely a cut or two above the usual pulp spy novel.