Imprisonment
The theme of imprisonment is shown by the constant presence of physical prisons in the novel, especially the Marshalsea. However, characters are imprisoned in other more subtle ways as well, including by social prejudice against them (Mrs. Gowan and Mrs. Merdle), vengefulness and bitterness on their own part (Miss Wade and Mrs. Clennam) or by their inability to mature and grow up (Flora and Maggy). Almost all characters are trapped in real or metaphorical prisons at some point in the novel, but the distinction between freedom and imprisonment is not clearcut. Amy's father being freed from prison actually makes her more constrained, because she now has to uphold rigid social codes of decorum as he demands. Both Pet Meagles and Fanny Dorrit find that the marriages they thought would bring them freedom and autonomy trap them in situations where they lack control. On the other hand, Arthur's imprisonment for debt finally frees him from his emotional blindness, as he realizes that he has loved Amy all along.
Poverty and wealth
Poverty and wealth are themes which obsess many of the characters in the novel. Money, or the illusion of having money, largely determines one's social position. For example, even though Mr. Merdle is awkward and dull, everyone makes a show of pretending to enjoy his company when they believe him to be wealthy. Shrewd characters like Mrs. Gowan are careful to give the impression of outward wealth, regardless of their circumstances. For these reasons, the restoration of the Dorrit fortune in the middle of the novel completely changes the possibilities of what this family can achieve: they can go places and interact with people that would otherwise have been completely out of their reach. Nonetheless, wealth is ultimately shown to be fickle, and an unstable source of happiness: through Mr. Merdle's treachery, characters including Arthur and the Dorrit family lose all their money. Arthur and Amy's happiness at the end of the novel is rooted in a commitment to live a modest and unpretentious life.
Pride
Even at moments when it seems absurd, most of the Dorrit family clings to a stubborn sense of pride. With the exception of Amy and Frederick, everyone else acts like they are of a high social rank and are very careful to protect their status and reputation. Their prideful behavior amongst fellow prisoners shows how Dickens critiques a basic human instinct to create social hierarchies in any situation. A prison seems like a place where everyone would be equal in their lack of privileges, but within the Marshalsea, a social system emerges which mirrors the elaborate social hierarchy of London at large.
Parents and children
In the novel, parents and parental figures consistently fail their children. Both Amy and Arthur are neglected in different ways: Arthur is alienated from his cold and distant mother, while Amy is shamed and taken for granted by her self-absorbed father. Mrs. Gowan and Mrs. Merdle treat their sons as pawns in their own social ambitions, and do not ultimately care about their children's welfare. Even Mr. and Mrs. Meagles, who seem to be loving and kind parents, fail to protect their daughter Pet from an unhappy marriage, and they also push away Tattycoram, who functions as a kind of surrogate daughter for them. Because parents are so often disappointing, there are often role reversals: Amy functions as the de facto parental figure in her family even though she is the youngest child, and her ability to be both responsible and emotionally nurturing is shown by Maggy calling her "Little Mother."
Bureaucracy
The theme of bureaucracy is mainly shown through the presence of the Circumlocution Office, although it also shows up in the complex structures of the Marshalsea. The Circumlocution Office creates the impression of an occupation for wealthy and fashionable men like members of the Barnacle family, and Edmund Sparkler, yet nothing ever gets accomplished. Doyce and Arthur create shock by trying to urge the office to actually take action, make decisions, and make things better for people. The presence of bureaucracy shows that appearances can be deceiving: the existence of an office does not mean that anything actually gets done. When Doyce is celebrated and rewarded for his invention in Russia, Dickens makes an unfavorable contrast between England and the supposedly backward Russia.
Travel
As soon as the Dorrits become wealthy, they go traveling, and they encounter many other characters while abroad. At the start of the novel, the core cast of characters also meets for the first time because they find themselves abroad. For those wealthy enough to enjoy the privilege, tourism was a way of displaying sophistication and showing off one's status. At the same time, an insistence on mostly associating with other English tourists and clinging rigidly to social standing meant that even traveling did not actually expand one's horizons very much because people mostly still interacted with the same people they usually did. Travel is not presented very positively, because Amy is too overwhelmed and lonely to appreciate the sights she is seeing, and would much rather stay in familiar settings with the people she is close to.
Deceit
Many of the characters in the novel lie and deceive others in order to protect themselves and their secrets. Most notably, Mrs. Clennam deceives her "son" for his entire life, and goes to great lengths to make sure the deception is not uncovered during her lifetime. Mrs. Gowan also stages an elaborate deception around her son's marriage in order to protect her social standing, while Fanny and Mrs. Merdle tacitly agree to a deception of pretending they do not know each other because it allows them to save face. Blandois is, of course, also a master of disguise and deception, but interestingly, he uses deception as a kind of business tool in order to successfully exploit others and make money. The other characters use deception to maintain social status or try to control others around them.
