Reading 1001 discussion

21. What is the significance of the discussion of "illusion" and the final words of the conclusion "a dream"?

That's a really interesting question. When Smiley is talking to Bill at the end Bill tells him "you had this one price. Ann. The last illusion of the illusionless man. He reckoned that if I were known to be Ann's lover around the place you wouldn't see me very straight when it came to other things." Then when Smiley is replaying this conversation in his mind he says to himself "Illusion? Was that really Karla's name for love?"

If illusion is meant to be love, then that explains why certain people refused to see the clues before their eyes. Emotional connections functioned as a way to distort the reality. Of course at the end, the reference to dream was meant to indicate that Bill loved Jim (a fact that had been brought up before). Jim was his father figure and hero and his love for him allowed him to believe that seeing the gun was a dream.