The novel has inspired several film adaptations.
At Russell Square, Miss Sharp is introduced to the dashing and self-obsessed Captain George Osborne (to whom Amelia has been betrothed from a very young age) and to Amelia's brother Joseph Sedley, a clumsy and vainglorious but rich civil-servant fresh from India. Becky entices Sedley, hoping to marry him, but she fails because of warnings from Captain Osborne, Sedley's own native shyness, and his embarrassment over some foolish behavior of his that Becky had witnessed at Vauxhall.
With this, Becky Sharp says farewell to Sedley's family and enters the service of the baronet Sir Pitt Crawley, who has engaged her as a governess to his daughters. Her behaviour at Sir Pitt's house gains his favour, and after the premature death of his second wife, he proposes to her. However, he finds that she is already secretly married to his second son, Rawdon Crawley.
Sir Pitt's elder half sister, the spinster Miss Crawley, is very rich, having inherited her mother's fortune of £70,000. How she will bequeath her great wealth is a source of constant conflict between the branches of the Crawley family who vie shamelessly for her affections; initially her favorite is Sir Pitt's younger son, Captain Rawdon Crawley. For some time, Becky acts as Miss Crawley's companion, supplanting the loyal Miss Briggs in an attempt to establish herself in favor before breaking the news of her elopement with Miss Crawley's nephew. The misalliance so enrages Miss Crawley, that she disinherits her nephew in favour of his elder brother, who also bears the name Pitt Crawley. The married couple constantly attempt to reconcile with Miss Crawley, and she relents a little. However, she will only see her nephew and refuses to change her will.
While Becky Sharp is rising in the world, Amelia's father, John Sedley, is bankrupted. The Sedleys and Osbornes were once close allies. The relationship between the two families disintegrates, and the marriage of Amelia and George is forbidden. George ultimately decides to marry Amelia against his father's will, primarily due to the pressure of his friend Dobbin, and George is consequently disinherited. While these personal events take place, the Napoleonic Wars have been ramping up. George Osborne and William Dobbin are suddenly deployed to Brussels, but not before an encounter with Becky and Captain Crawley at Brighton. The holiday is interrupted by orders to march to Brussels. Already, the newly wedded Osborne is growing tired of Amelia, and he becomes increasingly attracted to Becky.
At a ball in Brussels (based on the Duchess of Richmond's famous ball on the eve of the battle of Waterloo) George gives Becky a note inviting her to run away with him. He regrets this shortly afterwards and reconciles with Amelia, who has been deeply hurt by his attentions towards her former friend. The morning after, he is sent to Waterloo with Captain Crawley and Dobbin, leaving Amelia distraught. Becky, on the other hand, is virtually indifferent about her husband's departure. She tries to console Amelia, but Amelia responds angrily, disgusted by Becky's flirtatious behavior with George and her lack of concern about Captain Crawley. Becky resents this snub and a rift develops between the two women that lasts for years. Becky is not very concerned for the outcome of the war, either. Should Napoleon win, she plans to become the mistress of one his marshals, and meanwhile she makes a profit selling her carriage and horses at inflated prices to panicking Britons seeking to flee the city, where the Belgian population is openly pro-Napoleonic.
Captain Crawley survives, but George dies in the battle. Amelia bears him a posthumous son, who is also named George. She returns to live in genteel poverty with her parents. Meanwhile, since the death of George, Dobbin, who is young George's godfather, gradually begins to express his love for the widowed Amelia by small kindnesses toward her and her son. Most notable is the recovery of an old piano, which Dobbin picks up at an auction following the Sedleys' ruin. Amelia mistakenly assumes this was done by her late husband. She is too much in love with George's memory to return Dobbin's affections. Saddened, he goes to India for many years. Dobbin's infatuation with Amelia is a theme which unifies the novel and one which many have compared to Thackeray's unrequited love for a friend's wife.
Meanwhile, Becky also has a son, also named after his father, but unlike Amelia, who dotes on and even spoils her child, Becky is a cold, distant mother. She continues her ascent first in post-war Paris and then in London where she is patronised by the great Marquess of Steyne, who covertly subsidises her and introduces her to London society. Her success is unstoppable despite her humble origins, and she is eventually presented at court to the Prince Regent himself.
Becky and Rawdon appear to be financially successful, but their wealth and high standard of living are mostly smoke and mirrors. Rawdon gambles heavily and earns money as a billiards shark. The book also suggests he cheats at cards. Becky accepts trinkets and money from her many admirers and sells some for cash. She also borrows heavily from the people around her and seldom pays bills. The couple lives mostly on credit, and while Rawdon seems to be too dim-witted to be aware of the effect of his borrowing on the people around him, Becky is fully aware that her heavy borrowing and her failure to pay bills bankrupts at least two innocent people: her servant Briggs, whose life savings Becky borrows and fritters away, and her landlord Raggles, who was formerly a butler to the Crawley family and who invested his life savings in the townhouse that Becky and Rawdon rent (and fail to pay for). She also cheats innkeepers, milliners, dress-makers, grocers, and others who do business on credit. She and Rawdon obtain credit by they tricking everyone around them into believing they are receiving money from others. Sometimes, Becky and Rawdon buy time from their creditors by suggesting Rawdon received money in Miss Crawley's will or are being paid a stipend by Sir Pitt. Ultimately Becky is suspected of carrying on an extramarital affair with the Marquess of Steyne, allowed by Rawdon to prostitute herself in exchange for money and promotion.
At the summit of her success, Becky's pecuniary relationship with the rich and powerful Marquess of Steyne is discovered by Rawdon after Rawdon is arrested for debt. His brother's wife, Lady Jane, bails him out and he surprises Becky and Steyne in a compromising moment. Rawdon leaves his wife and through the offices of the Marquess of Steyne is made Governor of Coventry Island to get him out of the way, after Rawdon challenges the elderly marquess to a duel. Becky, having lost both husband and credibility, is warned by Steyne to quit England and wanders the continent. Rawdon and Becky's son is left in the care of Pitt Crawley and Lady Jane. However wherever Becky goes, she is followed by the shadow of the Marquess of Steyne. No sooner does she establish herself in polite society than someone turns up who knows her disreputable history and spreads rumours; Steyne himself hounds her out of Rome.
As Amelia's adored son George grows up, his grandfather relents and takes him from poor Amelia, who knows the rich and bitter old man will give him a much better start in life than she or her family could ever manage. After twelve years abroad both Joseph Sedley and William Dobbin return to England. Dobbin professes his unchanged love to Amelia, but although Amelia is affectionate, she tells him she cannot forget the memory of her dead husband. Dobbin also becomes close to George, and his kind firm manner are a good influence on the spoilt child.
While in England, Dobbin mediates a reconciliation between Amelia and her father-in-law. The death of Amelia's father prevents their meeting, but following Osborne's death soon after, it is revealed that he had amended his will and bequeathed young George half his large fortune and Amelia a generous annuity. The rest is divided between his daughters, Miss Osborne, and Mrs Bullock, who begrudges Amelia and her son for the decrease in her annuity.
After the death of old Mr. Osborne, Amelia, Joseph, George and Dobbin go on a trip to Germany, where they encounter the destitute Becky. She meets the young George Osborne at a card table and then enchants Jos Sedley. Becky has unfortunately deteriorated as a character. She is drinking heavily, has lost her singing voice and much of her looks, and spends time with card sharks and con artists. The book suggests that Becky has been involved in activities even more shady than her usual con games, but does not go into details. Since there have been earlier hints about Becky's early life with her father, some of which suggest that Becky was a child prostitute, the reader is tempted to draw the most unsavory conclusions.
Following Jos' entreaties, Amelia agrees to a reconciliation (when she hears that Becky's ties with her son have been severed), much to Dobbin's disapproval. Dobbin quarrels with Amelia and finally realizes that he is wasting his love on a woman too shallow to return it. However, Becky, in a moment of conscience, shows Amelia the note that George (Amelia's dead husband) had given her, asking her to run away with him. This destroys Amelia's idealized image of George, but not before Amelia has sent a note to Dobbin professing her love.
Becky resumes her seduction of Joseph Sedley and gains control over him. He eventually dies of a suspicious ailment after signing a portion of his money to Becky as life insurance. In the original illustrations, which were done by Thackeray, Becky is shown behind a curtain with a vial (presumably of poison) in her hand; the picture is labelled 'Becky's second appearance in the character of Clytemnestra.' (She had played Clytemnestra during charades at a party earlier in the book.) His death appears to have made her fortune.
By a twist of fate Rawdon Crawley dies weeks before his older brother, whose son has already died. Thus the baronetcy descends to Rawdon's son. Had he outlived his brother by even a day he would have become Sir Rawdon Crawley and Becky would have become Lady Crawley - the title she uses regardless in later life.
The reader is informed at the end of the novel that although Dobbin married Amelia, and although he always treated her with great kindness, he never fully regained the love that he had once had for her.
Never having known financial or social security even as a child, Becky desires it above all things. Nearly everything she does is with the intention of securing a stable position for herself, or herself and her husband after she and Rawdon are married. She advances Rawdon's interests tirelessly, flirting with men such as General Tufto and the Marquess of Steyne in order to get him promoted. She also uses her feminine wiles to distract men at card parties while Rawdon cheats them blind.
Becky makes a few mistakes. Marrying Rawdon Crawley in secret was a mistake, as was running off instead of begging Miss Crawley's forgiveness. She also fails to manipulate Miss Crawley through Rawdon so as to obtain an inheritance. Although Becky manipulates men very easily, she does not even try to cultivate the friendship of most women. Lady Jane, the Dobbin sisters, and Lady Steyne see right through her. Amelia and—initially—Miss Crawley are exceptions to the rule.
After George Osborne's death, Amelia is obsessed with her son and with the memory of her husband. She ignores William Dobbin, who courts her for years, and treats him shabbily until eventually he leaves. It is only after Becky shows her George's letter to her that Amelia realizes what a good man Dobbin is, although she has already written to him to ask him to come back. She eventually marries Dobbin.
The well-meaning Rawdon has a few talents in life, most of which have to do with gambling and dueling. He is very good at cards and pool, and although he does not always win he is able to earn cash by betting against less talented gamblers. He is heavily indebted throughout most of the book, not so much for his own expenses as for Becky's. Not particularly talented as a military officer, he is content to let Becky manage his career.
Although Rawdon knows Becky is attractive to men, he believes her reputation is spotless even though she is widely suspected of romantic intrigue with General Tufto and other powerful men. Nobody dares to suggest otherwise to Rawdon because of his temper and his reputation for dueling. Yet other people, particularly the Marquess of Steyne, find it impossible to believe that Crawley is unaware of Becky's tricks. Steyne in particular believes Rawdon is fully aware Becky is prostituting herself, and believes Rawdon is going along with the charade in the hope of financial gain.
After Rawdon finds out the truth and leaves Becky for an assignment overseas, he leaves his son to be brought up by Sir Pitt and Lady Jane.
A substantial part of the early section of the book deals with the efforts the Crawleys make to kowtow to Miss Crawley in the hope of receiving a big inheritance.
Raised to be a selfish, vain, profligate spender, George squanders the last of the money he receives from his father and sets nothing aside to help support Amelia. After marrying Amelia, he finds after a couple of weeks that he is bored. He flirts with Becky quite seriously and is reconciled to Amelia only a short time before he is killed in battle.
Later, Dobbin discreetly does what he can to help support Amelia and also her son George. He allows Amelia to continue with her obsession over George and does not correct her erroneous beliefs about him. He hangs about for years, either pining away over her while serving in India or waiting on her in person, allowing her to take advantage of his good nature. After Amelia finally chooses Becky's friendship over his in Baden-Baden, Dobbin leaves in disgust. He returns when Amelia writes to him and admits her feelings for him, marries her, and has a daughter whom he loves deeply.
Thackeray meant the book to be not only entertaining but also instructive, an intention demonstrated through the book's narration and through Thackeray's private correspondence. The novel is considered a classic of English literature, though some critics claim that it has structural problems; Thackeray sometimes lost track of the huge scope of his work, mixing up characters' names and minor plot details. The number of allusions and references it contains can make it difficult for modern readers to follow.
The novel is a satire of society as a whole, characterised by hypocrisy and opportunism, but it is not a reforming novel; there is no suggestion that social or political changes, or greater piety and moral reformism could improve the nature of society. It thus paints a fairly bleak view of the human condition. This bleak portrait is continued with Thackeray's own role as an omniscient narrator, one of the writers best known for using the technique. He continually offers asides about his characters and compares them to actors and puppets, but his scorn goes even as far as his readers; accusing all who may be interested in such "Vanity Fairs" as being either "of a lazy, or a benevolent, or a sarcastic mood".
The work is often compared to the other great historical novel which covered the Napoleonic wars: Tolstoy's War and Peace. While Tolstoy's work has a greater emphasis on the historical detail and the effect the war has upon his protagonists, Thackeray instead uses the conflict as more of a backdrop to the lives of his characters. The momentous events on the continent do not always have an equally important influence on the behaviors of Thackeray's characters. Rather their faults tend to compound over time. This is in contrast to the redemptive power conflict has on the characters in War and Peace. For Thackeray, the Napoleonic wars as a whole can be thought of as one more of the vanities expressed in the title.
The suggestion, near the end of the work that Becky may have killed Jos is argued against by John Sutherland in his book Is Heathcliff A Murderer? : Great Puzzles In Nineteenth-century Fiction. Although Becky is portrayed as having a highly dubious moral sense, the idea that she would commit premeditated murder is quite a step forward for the character. Thackeray was a fierce critic of the crime fiction popular at the time, particularly that of Edward Bulwer-Lytton. These lurid and sensationalist accounts—known as "Newgate novels"—took their inspiration, and sometimes entire stories, from the pages of The Newgate Calendar. What Thackeray principally objected to was the glorification of a criminal's deeds; it therefore seems strange that he would have depicted Becky as such a villainess. His intent may have been to entrap the Victorian reader with their own prejudices and make them think the worst of Becky Sharp even when they have no proof of her actions. This interpretation is not helped by the trio of lawyers she gets to defend her from the claims, Burke, Thurtell, and Hayes, named after prominent murders of the time (although this may have been further commentary aimed at the legal profession).
Though Thackeray does not settle definitively whether Becky murders Jos, such a development is in keeping with the overall trend of character development in the novel. The tone of Vanity Fair seems to darken as the book goes on. At the novel's beginning, Becky Sharp is a bright girl with an eye to improving her lot through marrying up the social scale; though she is thoroughly unsentimental, she is nonetheless portrayed as being a good friend to Amelia. By novel's end she is (implied to have become) an adulterer and a murderer. Amelia begins as a warm-hearted and friendly girl, though sentimental and naive, but by story's end she is portrayed as vacuous and shallow. Dobbin appears first as loyal and magnanimous, if unaware of his own worth; by the end of the story he is presented as a tragic fool, a prisoner of his own sense of duty who knows he is wasting his gifts on Amelia but is unable to live without her. Whether Thackeray intended this shift in tone when he began writing, or whether it developed over the course of the work's composition, is a question that cannot be settled. Regardless of its provenance, the novel's increasingly grim outlook can take readers aback, as characters whom Thackeray -- and the reader -- at first hold in sympathy are shown to be unworthy of such regard.
The character of Becky Sharp is based in part on Thackeray's maternal grandmother Harriet Becher. She abandoned her husband and children when she eloped with Captain Charles Christie. In 1806 shortly after the death of Christie and her husband she married Edward Butler, another army officer. Thackeray lived with his grandmother in Paris in the 1830s and again in the 1840s.
Chapter LXII, where the characters go off to Germany, preserves an image of that country which was to change drastically a generation later, following the Unification of Germany in 1871. Thackeray's characters, and the writer himself, have a clear image of Germany as a collection of picturesque, old-fashioned, harmless and rather comic principalities:
(...) Those snug, unassuming dear old operas in the German towns, where the noblesse sits, cries and knits stockings on the one side over against the bourgeoisie on the other; and His Transparency the Duke and his Transparent family, all very fat and good natured, come and occupy the great box in the middle; and the pit is full of the most elegant slim-waisted officers with straw-coloured mustachios, and twopence a day on full pay.
Evidently, the very last thing which Thackeray and English people of his generation could have imagined was that Germany was fated to become a major world power and Britain's bitter foe in two wars of unprecedented destructiveness.