The Book of Lost Hours

For fans of The Ministry of Time and The Midnight Library, a sweeping, unforgettable novel following two remarkable women moving between postwar and Cold War-era America and the mysterious time space, a library filled with books containing the memories of those who bore witness to history.

Enter the time space, a soaring library filled with books containing the memories of those have passed and accessed only by specially made watches once passed from father to son-but mostly now in government hands. This is where eleven-year-old Lisavet Levy finds herself trapped in 1938, waiting for her watchmaker father to return for her. When he doesn't, she grows up among the books and specters, able to see the world only by sifting through the memories of those who came before her. As she realizes that government agents are entering the time space to destroy books and maintain their preferred version of history, she sets about saving these scraps in her own volume of memories. Until the appearance of an American spy named Ernest Duquesne in 1949 offers her a glimpse of the world she left behind, setting her on a course to change history and possibly the time space itself.

In 1965, sixteen-year-old Amelia Duquesne is mourning the disappearance of her uncle Ernest when an enigmatic CIA agent approaches her to enlist her help in tracking down a book of memories her uncle had once sought. But when Amelia visits the time space for the first time, she realizes that the past-and the truth-might not be as linear as she'd like to believe.

Perfect for fans of The Midnight Library and The Ministry of Time, The Book of Lost Hours explores time, memory, and what we sacrifice to protect those we love.

From the publisher


Simon & Schuster/Atria Books | Aug 26, 2025 | 400 Pages | ISBN:9781668076347 |

"[An] engrossing debut….Gelfuso seamlessly blends elements of romance and fantasy into the twisty quest narrative, and packs excitement into every page. It's a delight." -Publishers Weekly

"Book clubs, fans of Kaliane Bradley's The Ministry of Time (2024), and readers who enjoy books about magical libraries will find much to enjoy and discuss in this intriguing novel." -Booklist

"The Book of Lost Hours by Hayley Gelfuso is a magnificent and complex feat of imagination, a love story that defies the boundaries of time, memory, and reality. From the very first wild page, you'll be swept into a world where the past isn't just remembered-it's lived, fought for, and protected at all costs. Luminous and haunting, Gelfuso's prose takes us on a journey through a tale of love that transcends time and space, an exploration of how far we'll go to hold on to what matters most. The Book of Lost Hours is a testament to the power of memory, the fragility of truth, and the enduring strength of the human heart. You'll never look at time the same way again." -Patti Callahan Henry, New York Times bestselling author of The Secret Book of Flora Lea

"There's a version of me, somewhere in another timeline, who never read The Book of Lost Hours, and I feel sorry for them. Hayley Gelfuso has written the kind of novel that doesn't just bend time-it stops it, folds it, and tucks a love letter inside. You don't read this book so much as vanish into it, and when you return, your heart is not the same as when you left. An astounding debut!" -Jamie Ford, New York Times bestselling author of The Many Daughters of Afong Moy

"A meditation on time, memory, and history, encased in a heart-pounding, cold-war spy thriller, wound tight around a sweeping story of love, family, and fate, The Book of Lost Hours performs actual magic-time itself stops as it draws you in. An undeniable debut by a glittering new talent." -Daria Lavelle, author of Aftertaste