Gilly Macmillan is the internationally bestselling author of eight novels:  WHAT SHE KNEW, THE PERFECT GIRL, ODD CHILD OUT, I KNOW YOU KNOW, THE NANNY, TO TELL YOU THE TRUTH, THE LONG WEEKEND, THE MANOR HOUSE (published as THE FALL in the UK) and THE BURNING LIBRARY, which will be published in the US on November 18, 2025 and in the UK on November 18, 2025 in ebook & January 29, 2026 in hardback.

A former art historian and photographer, Gilly studied at Bristol University and the Courtauld Institute of Art in London. She lives in Bristol, UK, with her husband and three children.

Her first novel, WHAT SHE KNEW, was a Target pick, a LibraryReads pick, an Indie Next pick, a Book of the Month pick, an Edgar award nominee, and an International Thriller Writers award finalist. THE NANNY was a Spring 2020 Richard & Judy WHSmith Book Club pick and TO TELL YOU THE TRUTH was named one of the best thrillers of 2020 by the New York Times.

Gilly’s novels have appeared on the New York Times, Sunday Times, Globe & Mail and Der Spiegel bestseller lists and have been translated into 25 languages. She’s been described as ‘one heck of a good writer’ (Wall Street Journal) and her novels have been praised as ‘nuanced, completely addictive’ (People), ‘riveting’ (Publishers Weekly), and ‘visceral, emotionally charged…heart-wrenchingly well told’ (The Daily Mail).