Tinker, Tailor, Soldier, Spy is a book that everyone should read. It’s not a perfect masterpiece of fiction, but boy is it good. If you saw the movie, directed by Thomas Alfredson you might be surprised by how the book differs (and yet not) from the plot of the movie. This is a good reason to read the book too.
John le Carré took a very long time to write Tinker, Tailor. The edition I read, had a very interesting forward by le Carré from 1991, in which he explains how his original draft for the novel revolved around Jim Prideaux, but he couldn’t make the story work from an internal point of view. The character of George Smiley didn’t exist in the first drafts, but his addition—as an outsider to the Circus (a thinly disguised MI-6) during the timeline of the story—solved myriad problems and propels the story into being one of the greatest spy novels of all time.