Clarissa, or, the History of a Young Lady is an epistolary novel by Samuel Richardson, published in 1748. It tells the tragic story of a heroine whose quest for virtue is continually thwarted by her family, and is regarded as the longest novel in the English language (based on estimated word count). It is generally regarded as Richardson's masterpiece.

Clarissa Harlowe, the tragic heroine of Clarissa, is a beautiful and virtuous young lady whose family has become wealthy only recently and now desires to become part of the aristocracy. Their original plan was to concentrate the wealth and lands of the Harlowes into the possession of Clarissa's brother James Harlowe, whose wealth and political power will lead to his being granted a title. Clarissa's grandfather leaves her a substantial piece of property upon his death, and a new route to the nobility opens through Clarissa marrying Robert Lovelace, heir to an earldom. James's response is to provoke a duel with Lovelace, who is seen thereafter as the family's enemy. James also proposes that Clarissa marry Roger Solmes, who is willing to trade properties with James to concentrate James's holdings and speed his becoming Lord Harlowe. The family agrees and attempts to force Clarissa to marry Solmes, whom she finds physically disgusting as well as boorish.