Man and Wife was Wilkie Collins' ninth published novel. It is the second of his novels (after No Name) in which social questions provide the main impetus of the plot. Collins increasingly used his novels to explore social abuses, which according to critics tends to detract from their qualities as fiction. The social issue which drives the plot is the state of Scots marriage law; at the time the novel was written, any couple who were legally entitled to marry and who asserted that they were married, either before witnesses or in writing, were regarded in Scotland as being legally married.
The novel has a complex plot, which is common in Collins' work. In the Prologue, a selfish and ambitious man casts off his wife in order to marry a wealthier and better-connected woman by taking advantage of a loophole in the marriage laws of Ireland.
The initial action takes place in the widowed Lady Lundie's house in Scotland. Geoffrey Delamayn has promised marriage to his lover Anne Silvester (governess to Lady Lundie's stepdaughter Blanche), who has incurred the enmity of her employer. The spendthrift Geoffrey is about to be disinherited and wishes to escape from his promise and marry a wealthy wife. Nevertheless, he is obliged to arrange a rendezvous with Anne, in the character of his wife, at an inn, and documents this in an exchange of notes with her. Subsequently, urgent matters force him to send his friend Arnold Brinkworth, Blanche's fiance, to Anne in his place. To gain access to her, Arnold must ask for "his wife". Although nothing improper passes between them, they appear to the landlady and to Bishopriggs, a waiter, to be man and wife.
Thus, both Geoffrey and Arnold might be deemed to be married to Anne, depending on the weight put on the spoken and written evidence. Most of the novel concerns Anne's, Geoffrey's and Arnold's attempts to clarify their marital status: