The Portrait of a Lady is a novel by Henry James, first published in 1881.
The main character in the novel is Isabel Archer, an American heiress who moves to London following her father's death, and later travels in Europe. Whilst in Europe, she marries an American, Gilbert Osmond, who has a daughter Pansy, supposedly from his first marriage. Unknown to Isabel, her marriage to Gilbert has been engineered by another American expatriate, Madame Merle.
The marriage between Isabel and Gilbert turns out to be an unhappy one, and it emerges that Gilbert has been having a long-standing relationship with Madame Merle, and that she is Pansy's mother.
Click here to see an e-book version of Volume 1 of The Portrait of a Lady.