This is a great mid-period Dickens written just about at the point where his optimism about human beings and his zest to improve the conditions of all the hapless grovellers is at the tipping point of being transformed by a horrible realisation that the corruption of the ruling classes, the venality of the middle classes and the ground-down-and-outness of the labouring men and women meant that only a root and branch revolution would do, reform would simply fail, be watered down by the circumlocutors, revolution was the only hope. 
 But he was terrified of revolution and wrote two books about his fear, Barnaby Rudge (which i haven't read yet) and A Tale of Two Cities, which I have. He knew that social upheaval uncorks the violence, he knew the highway to hell paved with good intentions. 
 So he was in a complete political bind. Couldn't go back, couldn't go forward. All his middle to late masterpieces are written from this agonised political dilemma. Beginning with Dombey and Son he gets gloomier and gloomier. 
 But being Dickens his genius covers the gloom with hectic merriment and gurning gargoylery, which we love.