Novelist Penny Vincenzi has died, aged 78.
She died peacefully on Sunday afternoon, according to a statement from her publisher Headline.
Vincenzi started out as a journalist, but went on to publish 19 books - 17 novels and two collections of short stories - selling close to 3 million copies for £18.5m since Nielsen BookScan records began.
Known for her sagas featuring family secrets, romance and strong women, her first novel, Old Sins, was released in 1989 and her last, A Question of Trust, in October 2017.
At the launch of her 19th book, a Question of Trust, last year, she said: "If nobody buys it, it will be my last book; otherwise, no, I don't want it to be my last book ... I still love writing and the whole process."
Headline said in a statement: "Her family, Headline and her agent Clare Alexander are sad to announce the death of their beloved Penny Vincenzi who died peacefully on Sunday afternoon."
Longer tributes will follow, a spokesperson for the publisher said, but added: "She was always supportive of other authors, was much loved by those who knew her in the trade, and became a friend to many."
Alexander, who co-agented Vincenzi with Desmond Elliott before his death in 2003, said although she was a bestselling author this "does not begin to describe the woman we all came to love so much".
"I came to realise that her special gift as a novelist was her love for her characters, and that came from her deep interest in not only the people in her imagination, but also in everyone she met," said Alexander. "She had such a generous gift of friendship, quite blind to whether someone was the boss or just making her a cup of tea. And that is why so many people in publishing will be devastated by her loss.
"For myself, I will miss her every day. She was a story-teller of such natural talent. But our relationship went so much deeper than the merely professional (although what success and what fun we shared!) Penny was an irreplaceable friend. Many of us in publishing were truly fortunate to have known her. And none of us will ever forget her."
Fellow authors have expressed their sadness and admiration for Vincenzi. Romantic novelist Katie Fforde said on Twitter "she was always so kind and supportive" , while Sophie Kinsella wrote: "I'm so, so sad about the death of Penny Vincenzi. She was a friend, inspiration and icon. I admired her so much, both as an author and just generally as a fabulous person."
Orion author Hannah Richell also spoke of Vincenzi's kindness and compassion: "I never met Penny Vincenzi but she wrote to me after my husband died and we exchanged letters and messages. She gave such compassionate advice. I'll never forget her kindness. Absolutely heartbroken at the news. My thoughts are with her friends and family."