The author of To Kill A Mockingbird has sued a literary agent she says tricked her into assigning him the copyright on the Pulitzer Prize - winning book.Harper Lee, 87, says Samuel Pinkus took advantage of her failing hearing and eyesight to transfer the rights and has failed to respond to licence requests. To Kill A Mockingbird was published in 1960 and is considered a classic. It has sold more than 30 million copies. Lee is rarely seen in public and declines almost all interview requests. The novel is the only published book by the author, who lives in Monroeville, Alabama. 'Irrevocable' interest In the lawsuit, Lee alleges that when her long-time literary agent, Eugene Winick, became ill in 2002, his son-in-law, Mr Pinkus, switched several of Mr Winick's clients to his own company. Mr Pinkus is alleged to have transferred the rights to secure himself "irrevocable" interest in the income derived from Lee's book. He also sought to avoid paying legal obligations he owed to his father-in-law's company for royalties, according to the lawsuit. It is further alleged that Mr Pinkus failed to respond to offers on e-book rights and a request for assistance related to the book's 50th anniversary. The lawsuit bids the court to assign any rights in the book owned by Mr Pinkus to Lee and asks that she be returned any commission he took from 2007 onwards. Mr Pinkus did not immediately respond to an email from Reuters news agency seeking comment. Set in Depression-era, small-town Alabama, To Kill A Mockingbird tells the story of a lawyer who defends a black man accused of raping a white woman.