SPOILERS:
I was slightly puzzelled by Dr Manette's letter that was read out in Charles Darnay's second trial. When I checked back to the chapter in which the Bastille was stormed, it seemed like M Defarge never found any letter. He sook out the tower in which Dr Manette had been imprisoned, but didn't find anything. So, was the letter a forgery? Why wasn't it produced at Darnay's first trial? OTOH, how is it that the story matched up with Mme Defarge's family history, and how come Dr Manette's face used to cloud over when he saw Charles Defarge?