Preface and scope
In his Preface Dickens asks readers to judge Little Dorrit as an integrated pattern rather than a series of instalments, offers a guarded apology for his caricatures (the Barnacles, the Circumlocution Office, public scandals) and notes his personal visit to the Marshalsea to secure local detail. The novel that follows interweaves social satire, mystery and domestic pathos around debt, bureaucracy and moral constancy.

Setting and principal figures
The action centres on Amy “Little Dorrit,” born and reared in the Marshalsea debtor’s prison, her affectionate but vain father (the “Father of the Marshalsea”), and her devoted labours for home and kin. Arthur Clennam, an enquiring, upright outsider haunted by a family secret, becomes the novel’s moral pivot. Around them orbit Mr and Mrs Meagles and their daughter Pet (Minnie), the inventive Daniel Doyce (Arthur’s partner), the officious Flintwinches, the inquisitive investigator Pancks (with Rugg), and a gallery of satirical types—the Barnacles and the Circumlocution Office—who embody institutional inertia and social pretence.

Plot progression and crises
Early scenes contrast quarantine chatter in Marseilles, the Marshalsea’s private economy, and Mrs Clennam’s austere household where a suppressed family document and an icy maternal pride set long consequences in motion. Little Dorrit’s quiet heroism and Arthur’s enquiries—into William Dorrit’s creditors, a missing codicil and the suspicious Frenchman Blandois/Rigaud—link intimate duty to public wrongs. Pancks and Rugg’s sleuthing uncovers a dormant claim indicating Mr Dorrit’s rightful inheritance; at the same time the financier Mr Merdle’s spectacular fraud and suicide shatter credit across society.

Collapse, imprisonment and blackmail
Financial contagion precipitates firm failures. Arthur, convinced of Doyce’s innocence, assumes public responsibility, resigns to creditors and is committed to the Marshalsea. Inside, human loyalties surface: John Chivery, Maggy, Tattycoram and Little Dorrit nurse and sustain him. Rigaud/Blandois, traced as a blackmailing interloper who once visited Mrs Clennam’s house, brazenly seeks to extort papers; Mrs Clennam’s attempt to intercept him ends in a catastrophic household collapse that leaves her mute and bedridden and exposes past suppression of a codicil.

Recovery and moral reckonings
Tattycoram and Meagles secure an iron box of papers; Doyce eventually returns prosperous; Meagles pursues and disrupts Rigaud abroad. The Dorrits briefly taste social ascent—Fanny’s marriage, fashionable patronage—but wealth’s corrosions and Mr Dorrit’s mental decline culminate in his quiet death. Ultimately legal and business obstacles are cleared: the family’s fortunes are reorganised, justice for past wrongs is set in motion, and Arthur and Amy, bound by mutual fidelity rather than ostentation, marry and leave the prison to a modest, purposeful life.

Themes and tone
Throughout Dickens balances satirical exposure of bureaucracy, finance and social vanity with compassionate realism about poverty, duty and personal honour. Little Dorrit’s constancy, Clennam’s moral steadfastness and Doyce’s industriousness anchor a narrative that indicts appearance and power while affirming practical goodness.