Six letters by To Kill a Mockingbird author Harper Lee to one of her closest friends could fetch as much as $250,000 (€221,000) at auction.
Four of the letters date from before 'Mockingbird' while Lee (inset) was caring for her ailing father, Amasa Coleman Lee, the model for her protagonist Atticus Finch.
The signed and typed letters were written to Lee's friend, New York architect Harold Caufield, between 1956 and 1961, according to Christie's, which is selling them on Friday.
In one, she writes about her "stunned" reaction to the huge success of the book, published in 1960 and made into a movie starring Gregory Peck two years later.
"We were surprised, stunned & dazed by the Princeton review," she wrote. "The procurator of Judea is breathing heavily down my neck - all that lovely, lovely money is going straight to the Bureau of Internal Revenue tomorrow."
In another letter she tells Caufield: "Daddy is sitting beside me at the kitchen table. ... I found myself staring at his handsome old face, and a sudden wave of panic flashed through me, which I think was an echo of the fear and desolation that filled me when he was nearly dead. It has been years since I have lived with him on a day-to-day basis."
The sale comes as Lee's second book, Go Set a Watchman, is set to be released in July. It was written before the Pulitzer Prize-winning 'Mockingbird' but takes place 20 years later.