Crime writer Ruth Rendell is in a critical but stable condition after suffering a stroke.
The 84-year-old, who also has a seat in the House Of Lords as a Labour peer, is best known for her series of novels featuring Chief Inspector Wexford.
The best-selling author had a "serious stroke" last week and is being looked after in hospital by her son.
Her publisher said: "Our thoughts are with Ruth and her family at this difficult time."
In a statement, Hutchinson - Penguin Random House said Baroness Rendell of Babergh had suffered a stroke on 7 January.
"Her son, Simon Rendell, is with her and thanks everyone for their concern.
"The family request privacy while the doctors assess the best course of treatment," the statement added.
With more than 60 titles to her name, Rendell's last book was The Girl Next Door, which came out last year. It was published along with a 50th anniversary edition of her debut novel From Doon With Death, which saw Inspector Wexford make his debut.
Wexford has appeared in more than 20 novels - the last of which came out in 2013 - and were turned into The Ruth Rendell Mysteries for ITV, with the late George Baker playing the lead role for more than 10 years.
The writer described her character as a "big ugly man", named after the Irish county where she had recently holidayed.
The taciturn inspector worked in Sussex and was prone to "feelings… about some small thing when a case was about to break, and the small thing always turned out to be vital and his hunch seldom wrong".
She had recently finished work on a new novel, which is set to be published as planned in the autumn.
Rendell also wrote psychological crime thrillers under the pen name Barbara Vine.
In 1996 she was awarded a CBE and in 1997 she was made a life peer.