The character of "Little Dorrit" was inspired by Mary Ann Cooper (née Mitton), whom Dickens sometimes visited with her family. It is a serialized novel published between 1855 and 1857, and discusses the shortcomings of government and society during that period. Dickens's anger in this novel focuses on the institutions responsible for imprisoning insolvent debtors who were unable to work to pay their debts. The Marshalsea, the prison in which Dickens's own father was imprisoned, was responsible for these cases. Much of the criticism in this particular novel is directed at the social safety net: industry, medical care, worker safety, the bureaucracy of the British Treasury, and the segregation based on the lack of communication between classes.