i thought it was ok. i wasn't too disappointed nor was i too impressed by it. it was easy to figure out who was the mole, so i ended up reading the rest of the book for the reasons and explanations that the author would provide. first part of the book, smiley is reminiscing how things were before the failed covert operation. second part of the book, he is interviewing everyone who was involved. by the time, the third part comes around (which happens very quickly after long passages about "the old times in the circus", the mole is revealed and everything is done and dusted. the fourth part (which is a few pages left until the end of the book) is the process of arresting the mole. there are no elements of suspense, twists or surprising revelations as one would expect in a spy novel. overall, the book is just like the idea of cold war itself - "cold", factual and dull. i hope the film won't disappoint.