OK, this post is going to be filled with SPOILERS, but it's the only way I can fairly review this book.

First, I totally understand why the book is considered a smash-up of The Midnight Library and The Ministry of Time, but I would throw in Interstellar because of the parent-child dynamic and the willingness to bend time to preserve it.

I like all things time travel and a story wrapped around the middle part of the 20th Century was a great construction. The "lovers in all possible universes" was rewarding to the reader, though I have to admit I figured out who Moira was pretty early on.

Fair warning to one and all: keep track of the dates at the beginning of each chapter as they jump around a bit. This is not a flaw in the storytelling, just sometime to keep front of mind for the sake of your own sanity.

That said, I liked themes of sacrifice, lost love and rediscovered love. The mirroring of the relationships between Lisavet and Ernst and Amelia and Anton were well played and the ending was more satisfying than I expected.

Chapter 24, however, I'm still not sure about. And I am curious what historical events where "changed" because time had not been tinkered with (too much of For All Mankind is probably swirling around in my head).

The Book of Lost Hours is a good read told at an enjoyable pace that keeps you wanting to read just one more chapter.

I received a free DRC of this book through Netgalley. Lisavet grows up in a safe space outside of time thrust there by her father before the Nazis killed him. But she was mostly on her own until she falls in love with one of the timekeepers. To protect him, she had to let him go, but will the others let her go? The story travels back and forth between different locations and times as we find out how time and memories can be manipulated. This is a book that you need to pay complete attention to with all of the jumps in time. It had some interesting premises about how time and memories work. It's good to look for the helpers especially in times of crises.

What an interesting and often philosophical take on time and dimensionality and what the value of human experience and collective history is in the form of memories.

There are two main timelines: 1930s-1950s and 1960s.

To save her from the Nazis on Kristallnacht, Lisavet's father pushed her into the Time Space where memories are held within books for each person. Her father is a watchmaker whose time pieces allow one to travel into the Time Space. In there, Lisavet spends multiple years preserving memories into a book after seeing government agents entering in and out to delete the memories that serve to maintain the collective memories of their political agendas.

The second timeline is of Amelia who has lost her uncle Ernest who raised her after her mother passed away. Amelia is caught up with Moira who is part of the CIA who has enlisted her help in recovering this book that Lisavet had. Amelia's uncle was one of the government agents who had met Lisavet in the Time Space.

There are a lot of twists in this story which were predictable but nonetheless interesting to read.

Thank you NetGalley for the opportunity to review this book! #CampNetGalley

this book was so, so good! i loved how big the plot felt without ever getting confusing, and it kept surprising me over and over again. watching all the different storylines click into place was really satisfying, and you can tell how intentional every part of it was.

the character dynamics were genuinely so well done, and the couples in this story were so top tier. the writing was beautiful but still easy to sink into, and the pacing made it hard to put down! this is the kind of book that reminds you how good it feels to get lost in a story!! definitely recommend :)

thank you to netgalley and atria books for the arc!

This was such an interesting and entertaining read! I really enjoyed all of the POV's and felt like the characters were unique and developed. The multiple timelines were done super well and I had an easy time following the story! It felt wordy at times, but there was always plot progression taking place. After the 45% mark, everything fell into place and the story truly took off.

I enjoyed the historical setting of this book. The current events that were taking place at this time were not directly mentioned much, but the characters' actions and opinions felt very fitting to the time period. I also think the detachment from major current events from Lisavet made sense considering she lives most of her life in the form of others pasts.

I do think the romance felt like the most obvious plot point. It was really well done though, and I felt myself caring about the happiness of the characters and hurting with them as they worked through their struggles. This applies to not only this book, but many others that have been released over the years: Romance does not detract anything from main or deeper-meaning themes just because it's included in a novel. It simply makes it easier for many readers to connect with the story and subsequently digest heavier topics that can be threaded throughout.

The overarching theme was beautiful and felt very fitting with today's censorship, biased media, and the extremely active political attempts to skew history. 1984-ish vibes; "Who controls the past controls the future. Who controls the present controls the past." The ending was a very full circle moment that tied things up neatly while still leaving the reader with the sense of endlessness.

ARC provided for an honest review.

The Book of Lost Hours is a timeline traveling story of a young girl, Lizabet Levy, who has grown up in the space between time because she is unable to return to the usual timeline. She learns secrets of the Timekeepers and of time itself, and this lovely story unfolds a tale of love, patriotism, and the nature of memory itself. It gives off a fairy tale vibe throughout the whole novel.

This book would be an excellent pick for someone who loved The Secret Life of Addie La Rue or The Timekeeper’s Wife and similar novels that bend the boundaries of reality and time. Thank you to Atria Books for providing this book for review consideration via NetGalley. All opinions are my own.

I just got this yesterday and I'm already finished!!!! I love the whole story. Books and libraries, memories and mystery all in one! I couldn't put this down until I got to the end.

Not quite what I was expecting, but I went it blind and wasn't disappointed, this is a blend of gothic, historical fiction and fantasy. I read it fairly quickly over two days, but definitely worth it and a solid read for 2025. .

Thank you NetGalley and Atria Books for an E-ARC of The Book of Lost Hours!

Wow, wow, wow! Genre-blending, heart pounding, thought provoking, emotional, this novel has it all and will stay with you long after you have finished. I loved the historical fiction aspect of this novel, while also telling a love story, and providing a thrilling mystery.

The characters are extremely well developed, and I found myself sharing in their joys, as well as sorrows. Hayley Gelfuso drew me in from the very first page and I did not want the journey to end.

Grateful to #NetGalley for the ARC!

The secrets of the time space are kept by lineages of watch-makers, who are capable of accessing the massive library holding the memories of all those who have died by opening portals using magical watches. Lisavet Levy's father was one such watch-maker and on Kristallnacht, he hides his daughter in the time space before he is murdered. While in the time space, Lisavet witnesses soldiers destroying memories to rewrite history and makes it her mission to preserve as many memories as she can. In 1968, Amelia Duquesne is an orphan who had been in the care of his uncle until his untimely death. After his funeral, a woman who had worked with her uncle comes to Amelia to teach her to use the watches to enter the time space and to find the book her uncle had been searching for.

This book had a unique premise and the time space was incredibly imaginative and vividly described. The book is entertaining and the plot moves quickly. This reads a bit like a YA or new adult novel to me, in that it very focused on the action on the page and it made for a very quick read. I think this book would be an excellent beach or vacation read!

Hayley Gelfuso's "The Book of Lost Hours" is an absolute masterpiece, a truly immersive and unforgettable reading experience that earns every one of its five stars. From the very first page, I was completely captivated by Gelfuso's exquisite prose and her remarkable ability to weave a tale that is both deeply personal and sweepingly epic.

The premise alone is intriguing, but it's the execution that truly shines. Gelfuso crafts characters who feel incredibly real, their joys and sorrows palpable on the page. I found myself rooting for them, grieving with them, and celebrating their smallest victories. The intricate plot unfolds with a masterful pace, revealing layers of mystery and emotion that kept me eagerly turning pages late into the night.

What truly sets this book apart is Gelfuso's evocative world-building. Whether she's describing the dusty corners of an ancient library or the vibrant pulse of a forgotten city, her descriptions are so vivid you can almost taste the air and feel the textures. This rich tapestry of settings serves as the perfect backdrop for a story that explores profound themes of time, memory, loss, and the enduring power of connection.

"The Book of Lost Hours" is more than just a story; it's an experience. It’s a book that will linger in your thoughts long after you've read the final word, prompting reflection on your own lost hours and the moments that truly define us. If you're looking for a novel that is beautifully written, emotionally resonant, and utterly compelling, do yourself a favor and pick up "The Book of Lost Hours." It's a journey you won't regret.

The Book of Lost Hours by Hayley Gelfuso is an astonishing, genre-blending achievement, equal parts emotional, cerebral, and spellbinding. A masterclass in dual timelines and narrative cohesion, this book weaves together elements of science fiction, magical realism, historical fiction, and ethical inquiry, all through the deeply human lenses of love, family, survival, and sacrifice.

Told across multiple decades and perspectives, the story never loses its grip on the reader. The dual timelines are executed flawlessly—distinct, emotionally resonant, and interwoven with revelations that land with impact. The transitions between timelines feel deliberate and rewarding, with each chapter adding depth and clarity to what came before. If ever a novel begged to be adapted into a limited series, it’s this one.

At the heart of the novel is a fierce and resilient female protagonist who grounds the more fantastical elements of the plot in something deeply real: her fierce protective love. Her strength is never performative—it’s quiet, feral, and believable, and she forms the emotional backbone of the story. The characters across generations are fully realized, making the book not just a time travel epic but an exploration of how legacy and love reverberate through time.

The science is a triumph here. Gelfuso makes the theoretical feel intimate and the complex feel coherent. The time travel mechanics and ethical ramifications are explained in a way that’s accessible without ever being dumbed down.

What truly elevates the novel is Gelfuso’s writing and pacing. She trusts her reader. Hints are scattered subtly but meaningfully, and the reveals never feel forced, they’re crafted with elegance and layered intention. The story doesn’t hinge solely on its twists, but rather how each revelation reshapes the emotional core of the narrative..

For readers who like:
-Dual timelines
-Historical fiction
-Strong, complex female leads
-Intergenerational stories of love and loss

Final Verdict
The Book of Lost Hours is a devastatingly beautiful novel that balances science and magic, intellect and emotion. It’s a love story wrapped in a time loop, a reflection on the consequences of our choices, and a powerful exploration of legacy. Hayley Gelfuso has written something unforgettable and with just one book, she’s earned a spot as an auto-buy author on my shelf.

Grateful to NetGalley, Atria Books and Hayley Gelfuso For the opportunity to read an advance copy of this story in exchange for an honest review.

Heartbreaking and beautifully intriguing story about time and memories. Two women, connected by a secret library containing all the memories of time, try to stop the destruction and loss of important memories. I can't stop thinking about the characters. I love stories about secret libraries and their keepers.

DNF @ 60%. I honestly just don't care what happens in this story. I liked The Midnight Library well enough, and LOVED The Ministry of time; both are comps for this book, and while I can see why those were comped, this isn't as good as either of them. All of the characters come across as very flat and the emotion is sorely lacking from the story, which makes the stakes seem incredibly low when they should actually be incredibly high. Gelfuso hasn't succeeded in writing romantic tension OR suspense tension, both of which this story should have in spades. I do think she has struck on a good way of doing a time-travel romance, which is having the romance take place outside of time itself, but the rest of the story just isn't there.

I read The Book of Lost Hours in one sitting. I had to know how each timeline connected, how the characters fit together, and what the hell was actually happening in the time space. Hayley Gelfuso is a master storyteller. She doesn’t just write—she weaves. Every thread matters. Every choice lands.

Lisavet broke my heart. Eleven years old, hidden in a library of memories while the world outside burns. Her father disappears, and she’s left to wander through other people’s pasts. Years go by. She learns that timekeepers are slipping in and erasing memories. She decides to fight back.

Then comes Amelia in 1965. Her uncle is dead. The CIA shows up with a strange book and a mess of secrets. Amelia doesn’t know who to trust, but she knows something isn’t right. Her story could’ve felt distant, but it doesn’t. It aches in the same places Lisavet’s does.

This is a time-travel story. A memory story. A love story. It’s about who gets to decide what’s remembered and what gets erased. It’s about survival and resistance and finding your way through the wreckage.

I couldn’t put it down. I didn’t want to.

The Book of Lost Hours is a dark, atmospheric fantasy novel that blends gothic mystery with themes of grief, magic, and self-discovery. Hayley Gelfuso’s writing is lyrical and immersive, pulling readers into a richly detailed world where every shadow seems to hold a secret.

The story centers on a young woman grappling with loss, as she uncovers hidden truths about her family and herself. The magic system is unique and haunting, revolving around time, memory, and sacrifice. Gelfuso skillfully weaves in themes of longing, regret, and the price of power, making the emotional stakes feel deeply personal.

What really stands out is the moody, almost hypnotic atmosphere—readers who enjoy gothic tales with lush prose will likely be captivated. The pacing is deliberate, allowing the mystery to slowly unravel while keeping readers intrigued by the eerie setting and unpredictable twists.

Fans of The Invisible Life of Addie LaRue or The Ten Thousand Doors of January will likely appreciate this novel for its blend of melancholy beauty and magical realism.

In short: A beautifully written, atmospheric tale of grief, magic, and hidden secrets that lingers long after the last page.

This was such a creative and fun read. If you liked The Midnight Library, this is definitely a good fit for you. Time is almost its own character in the book, which is such an interesting concept.
Overall, this was an excellent read. I was very excited to read it, and it did not disappoint.
I would like to thank Net Galley and Atria Books for the opportunity to read this as an ARC. The ARC was provided by the publisher via Net Galley in exchange for an honest review.

I very much enjoyed The Book of Lost Hours by Hayley Gelfuso but it took me a little while to get into and isn't the fastest-paced book to read. It does raise some interesting questions about what benefit the historical narrative has and how who controls that can change the entire thing. If you loved The Ministry of Time (as I did) you might find this enjoyable.

Thanks to Netgalley and Atria for the ARC.

Kind of a spy novel with a dash of The Book of Doors.

Lisavet is shoved into a time tunnel by her father during the kristallnacht to keep her safe. But then he’s unable to come after her.

She spends more than a decade alone among the shelves of memories trying to save memories for being damaged or erased by spies from various government agencies.

While doing this she means a member of the CIA and falls in love with which makes things complicated.

I’m not usually a thriller/spy genre fan but the humanity in this story, particularly the hubris of men thinking they can and should control history.

This was such a creative and fun read. If you liked The Midnight Library, this is definitely a good fit for you. Time is almost its own character in the book, which is such an interesting concept. I loved the world building that was based around that idea, the rules she built for Time, and how she broke those rules. I don't want to give too much away, but I will say, there were some twists I saw coming, and some I didn't. Some things she brought full circle so beautifully that you just smile and go, oh. Yes that is absolutely right.

I took one star off because the end felt like it could've been wrapped up sooner. You get to those last few chapters and go, man that was the perfect way to end that. And turn the page and there's more. Then you get to the end of that and go, oh ok. Yes, that wraps up nicely. Then there's more. Lol.

Other than that, I enjoyed this book and do recommend it!