A Book of Nobodies

Dickens originally planned to name the novel Nobody's Fault, and though he changed the title, the theme of nobody remains a part of the work.  Many characters struggle with their identity throughout the novel.  One major reason for that struggle is the inability to define oneself through the family entity.  In the case of Miss Wade and Tattycoram, one's family is a mystery and both characters show a reluctance to adapt themselves to a familial unit.  Another cluster of characters deal with the loss of a parent:

*Clennam returns to London after the death of his father.
*Little Dorrit's mother dies soon after her birth
*Flora's mother as well as that of Young Chivery is never identified
*Edmund Sparkler is the son of Mrs. Merdle from a previous relationship

In addition to this, Pet Meagles deals with the loss of a twin sister while Maggy shows her confusion with her identity by calling the younger Little Dorrit "Little Mother."  Mrs. Clennam admits she is not Arthur's mother, a fact he learns after the novel ends.  Because of these issues, many characters have trouble coming to terms with their identity and understanding who they are.

Interestingly, two of the strongest family units in the novel are opposites.  On one hand are the Barnacles, a strong family, though corrupt, that runs England and never relinquishes power.  All positions of power remain within the family.  Though Dickens portrays this family and politically corrupt, he uses the Barnacles to show the power possible to a strong family unit.

On the other hand are the Plornishs, an extremely poor, though honest, family that lives in Bleeding Heart Yard.  Mr. Plornish is a hard-working plasterer, who has trouble finding work in order to feed his wife and many kids.  Nevertheless, the family is always happy and willing to help others.

Ultimately, the novel is about a bunch of nobodies trying to find their role in the world.  Dickens shows that the lack of knowledge about one's identity makes finding that role difficult.