Author Norman Mailer is recovering in hospital following surgery to remove scar tissue from around his lung.
Mailer is one of America's major literary figures
Mailer, 84, had an operation about a week ago, said his editorial assistant Dwayne Prickett.
"He had some breathing problems," he said, adding that Mailer was improving every day.
The writer has won the prestigious Pulitzer Prize twice, for The Armies of the Night in 1968 and The Executioner's Song in 1979.
Mr Prickett said everyone "was cautious" because of Mailer's age.
Mailer's daughter Salina said her father was "getting better every time I see him".
Mailer's latest work, The Castle in the Forest, was published earlier this year.
Born in 1923 in New Jersey, Mailer has written dozens of books as well as plays, poems, screenplays and essays. He was co-founder of The Village Voice alternative newspaper in New York.
He is known for his biting prose and as an antagonist of the feminist movement.
His first major success, the novel The Naked and the Dead, was a fictionalised account based on his experiences in the Army in World War II.