I was utterly entranced throughout the entirety of this novel!! From the first chapter, to the last chapter, I couldn’t read this book fast enough! The writing was absolutely beautiful, the storyline completely original, and the characters made sense, they worked so well together, and were so well rounded!! This is a book about fantasy, love, even a little mystery. Hayley did a fantastic job with this novel! Thank you to Netgalley and Atria books for an ARC of this novel!!

In this book we follow Lisavet Levy. A German girl, during postwar and cold war America, who has an interesting relationship with time.
I loved the way she connected with time, it felt like an original idea. I thought the mystery wasn't much of a mystery from the get go. Then halfway through the book I realized that wasn't the point and all the pieces of the story actually started to come together in a way that had me gripping my kindle and reading as fast as I could.
The end had me in tears. It was so good. I definitely recommend this book to anyone who likes sci-fi and historical fiction.

Are memories real? What about time? What if you could change everything? Would you destroy it all to save the ones you love? Would you destroy yourself?

I loved this. Definitely recommend.

Thank you to NetGalley and Atria Books for providing an e-arc in exchange for my honest review.

Welcome to "the place where Time ends".
When I read the description of The Book of Lost Hours I just knew I had to read it, as it had some of my favorite things: book about books and a magical library; multiple POVs; dual timeline; parenting.

And I was right, I absolutely loved it! I felt as if I were in a movie while reading this book: the descriptions, the atmosphere, the political climate in both timelines, and how Hayley Gelfuso has us accompany the characters as they grow year after year and we witness the choices they make - good and questionable ones. Like we're time walking, ourselves.

Throughout the book, we witness the politics around time walking and the ongoing pursuit to keep only government sanctioned memories/history (censorship, truly). But more than that, what really spoke to me were the lengths to which a mother will go to protect their child, and how parenthood utterly shifts one's priorities, view of the world and sacrifices we're willing to make.

I'd recommend this book for lovers, like me, of The Invisible Life of Addie LaRue and The Night Circus.

Favorite quotes:
"Time is the beast that makes mortals of all one way or another. It takes everything, heedless of wealth or status."
"Obedience may make for good soldiers, but it makes for even greater tragedies."
"Living was not the most dangerous thing after all. Loving was."

Obsessed. There were plot twists that I saw coming and I was SO excited when they happened. The ending of this book had me sad, in a good, excited for the character’s futures way.

The story reminds me of Midnight Library and Ink, Blood, Sister Scribe.

[arc review]
Thank you to NetGalley and Atria Books for providing an arc in exchange for an honest review.
The Book of Lost Hours releases August 26, 2025

2.75

In 1938, on the night of Kristallnacht, Lisavet’s father hides her in the time space, in which she becomes trapped for many years to come when her father fails to return for her.
Soon, Lisavet discovers other timekeepers who enter the time space with the motive to destroy select memories contained within books, effectively preserving their desired version of history.

During the late 1940s, Lisavet crosses paths with an American timekeeper named Ernest, who tries to stop Lisavet from creating her own book of memories, comprised of ones she has saved and collected that otherwise would’ve been destroyed.

Then, in 1963, we meet Amelia — the grieving niece of Ernest who is sent into the time space and is tasked with recovering Lisavet’s lost book of memories.

I think fans of <I>The Ministry of Time</I> will really love this debut. Personally though, I thought that the story had pacing issues and was unnecessarily drawn out.
For a character that literally has a coming-of-age by living through the memories of other people, I had hoped for a more immersive and diverse reading experience.
The plot and character twists could be seen from miles away, and ultimately, I was ready for things to be wrapped up by the halfway point.

This story offers a richly imaginative blend of historical fiction, fantasy, and mystery. The concept of the time space—a vast, secret library of memories accessible only through heirloom watches—is both original and haunting. Lisavet's journey, from abandoned child to memory-keeper defying government censors, is emotionally resonant and deeply compelling. Her resilience and quiet rebellion highlight themes of memory, loss, and the power of truth.

Amelia’s storyline in the 1960s adds a fresh layer, connecting past and present while raising questions about how we understand history and who gets to preserve it. The dual timelines weave together beautifully, and the evolving mystery keeps the reader invested. Overall, this tale is a poignant exploration of legacy, agency, and the fragile line between reality and remembrance. It's perfect for fans of introspective speculative fiction with emotional depth and historical intrigue.

Review of free ARC from NetGalley, in exchange for an honest review.

I really enjoyed reading this one, it is a very original concept! This book floats back and forth between two different girls' stories, decades apart but both being introduced to a place referred to as the time space. And, both learning about timekeepers while discovering secrets about their family's. All set during some very tumultuous time periods in our history.

There are a few cons to this book. The going back and forth in the narrative from one character to another can be something that makes a lot of people disinterested in a book early on (both living in different times in history but still following each one's story in their chronological order). I connected more with Lisavet, than Amelia, as Amelia just did not seem to have the depth in the way she was written. This may be on purposes, though, as Lisavet is obviously the focus. Also, the first half or so moves fairly slowly, a lot of conversation and very little plot movement.

But overall, it is definitely a concept I have not seen before, which gives it that uniqueness needed in another book about time travel adjacent themes. The way the time space and memory library works is interesting, and there are definitely a few thought-provoking scientific ideals. The author writes it in a way where you can step into each character's head, with a distinct difference to how each perceives things. I figured out the twists pretty early on in the book, but it really didn't deter me from finishing the book out because it was still very interesting.

I would like to thank NetGalley and Atria books for allowing me to read an eARC of this book in exchange for an honest review.

It was advertised as "Perfect for fans of The Midnight Library" which is is one of my favorite books, and I would add on to that that it also has 'The Invisible Life of Addie LaRue' and 'The Time Traveler's Wife' vibes. as well. It was one of my most anticipated reads of the summer and this book did not disappoint!! Fans of cinematic love stories through time and history will definitely want to check this one out.

The Book of Lost Hours primarily follows the lives of Lisavet Levy (in the past) and Amelia Duquesne (in the present) as they encounter the 'Time Space' (a place outside of time where memories are stored) and governments trying to control it, and by default, all of history. There are also several other key characters: Ernest (a timekeeper and Amelia's uncle), Moira (head of the TRP), Jack (head of the CIA and the villain of the story), Azrael (a helpful specter in the time space), and several other timekeepers and rebels for the cause). As the story goes on, the web of connections gets more complex and there are SURPRISING REVELATIONS (no spoilers).

The telling of their stories is done through each of their POVs, pinging back and forth in time. It is an interesting structure, but gets off to a slow start and really starting to pick up in the second half of the book. The writing is very well done, the characters are well-developed, and the setting(s) feel so real and atmospheric! The romance in this story is not the primary plot, but still comes through strong and will give you all the feels. I feel like the ending was well-written and nicely wrapped -- no cliff-hangers or unresolved plot.

This book was wild and wonderful! A piece of speculative fiction, yet rooted both in real-world history and science. It's one of the best books I've read this year so far! I highly recommend this one!

I loved the concept of this book. I’ve read others with the same baseline - time travel or being able to insert yourself into book - but this spin was really interesting! This was about the ability to time travel through memories of people that are stored in books in another dimension (time space). Just like any other political climate, the government tries to control the narrative but by destroying memories that don’t benefit them.

I felt connected to every character and felt that they were all very fleshed out and nothing ever seemed forced with them. The connections between them felt real and genuine. The feelings they felt didn’t seem forced or over the top. I really enjoyed how they all connected in the end and how the story came full circle.

This was a great debut novel for Hayley and I can’t wait to get my hands on more from her!

The Book of Lost Hours is a creative and atmospheric debut that blends historical fiction, speculative fantasy, and emotional coming-of-age. Hayley Gelfuso introduces readers to a stunning concept - The Time Space - a plane of existence that manifests as a library of memories, tucked away in a fold of time and accessed by intricately crafted watches.

The novel weaves between two interconnected timelines—Lisavet Levy, a German Jewish girl abandoned in The Time Space beginning in 1938 on The Night of Broken Glass, and 1965, when an American teenager, Amelia Duquesne, is reeling from the death of her guardian and uncle only to be recruited into the Temporal Reconnaissance Program (TPR), a department in the CIA responsible for managing memories in The Time Space.

The novel started to drag a bit early on, mostly because the big reveals were just too easy to guess, sorry. Once that hint was dropped, I found myself just waiting for the story to catch up to the inevitable reveal. By the time it finally happened, it had taken so long that the moment felt more "finally, can we move on" than impactful. Also, the personalities just felt so off and jarring, even knowing the truth.

Unlike The Midnight Library, The Book of Lost Hours has much higher stakes and more intense characters—government agencies trying to regulate, control, and assert power over time and memory can be intense. Then there are the sweet and gentle moments in The Time Space of youth, love, and adventure - these softer moments sometimes get overshadowed by the intensity of those power dynamics.

I’m sure The Book of Lost Hours will find a wide and appreciative audience when it comes out.

I don’t really know where to start with the review for this book. It was everything! I loved so much about this story and I just want everyone to read it so we can talk about it!

In a nutshell The Book of Lost Hours is historical/speculative fiction, romance, mystery, sci-fi and magical realism. A time bending multi dimensional novel that encompasses so much it’s mind boggling that it’s a debut.

The “Hours” explores Time space which is a library outside of time that houses a vast collection of memory books accessible with heirloom watches. Those with watches are granted the ability to access the collective memory consciousness. Different governing bodies have varying approaches on history and how it should or should not be preserved. The “Hours” explores our collective experience of history and how it determines our future, a theme accurately on point for our current global political climate.

We follow Lisavet, Ernest, Amelia and Moira through dual timelines initially starting in 1938, Nuremberg, Germany and 1965, Boston, Massachusetts. Their stories converge and intertwine in ways that are not expected. The main characters are morally grey at times but you can’t help but to understand their motives. The love story is poignant and heart breaking. Asking what would you sacrifice for those you love?

The “Hours” is an exploration of memory, history, time, alternate dimensions, reality, family and agency. It is more than time travel as it provides a unique insight into how we construct our world and the roles we individually play in our current reality.

Thank you Atria Books for providing this ARC for review consideration via NetGalley. All opinions are my own.

This book has me hooked from the beginning. It is everything I want and what I’ve been searching for in a library time travel book. THIS was IT 😍. Thank you Netgalley for the chance to read the ARC for Summer Camp series. Really good job Hayley Gelfuso and Atria Books. I don't want to name them all but I have been reading so many library/time travel books, looking for the perfect one. I enjoyed this book from start to finish. It was so well written. I can't wait to hear the Audiobook.

4⭐️
"I'll take care of you. I won't let anything happen to you.
I'll rewrite all of history if I have to."
Wow. This was seriously so good. From the moment I read the first page I was hooked, right up until the end. This felt like such a unique story, about a girl lost in time and the lengths people will go to for the ones they love. In 1938 Lisavet Levy is hidden in the time space by her father, only to never see him again. She spends her time walking through memories with the ghost Azrael, separated from her life and the world outside. In 1965 15 year-old Amelia is grieving the death of her Uncle Ernest when she is tasked with finding a lost book of memories that he was searching for.

I really loved the chapters with Lisavet in the time space. It was so atmospheric I could picture it so easily in my mind. I loved Amelia learning languages and art and sciences alongside history, gently being guided by Azrael. And once she meets Ernest? God they were so cute, just so gentle and wholesome with each other. It was also a little bittersweet to read them, because we know what Ernest's timeline leads to in 1965.

I didn't enjoy the 1965 timeline quite as much, but I think that was more because when we jump into it we're only given half the answers. Amelia is approached by the CIA and really doesn't have any clue about what's going on or who to trust. This plotline really kicked up in the second half of the book though!

In terms of plot, I don't want to say too much to avoid spoiling anything. I will say, by the conclusion things sort of felt like they had lost their meaning. Like what had these characters really been fighting the entire book for?

Thank you to Netgalley and the publishing team for the ARC in exchange for an honest review.

Rating: ⭐⭐⭐⭐ (4/5)

Thank you to NetGalley and the publishers for providing me with an e-ARC of this upcoming book.

Historical fiction is typically not my genre. But this story was truly wonderful. I loved the characters and the story. The writing was lovely and the story amazing. The beginning moved a little slow for me, but it quickly took off. I would recommend this book to those who enjoy historical fiction and fantasy/sci-fi.

What if history wasn’t fixed but fragile?
This book takes that question and cracks it wide open, delivering a story that feels like Sarah’s Key got handed a second chance one where memory, legacy, and truth have the power to reshape everything.

But don’t be fooled: this isn’t just historical fiction with a soft edge. It’s Loki meets Agent Carter, with a time-bending premise that fuses espionage, family secrets, and ethical what-ifs into a fast-paced, emotionally intelligent narrative.

Told through multiple points of view, the story doesn’t just explore different characters it tests them. You’ll question every motive and wrestle with what it means to rewrite the past or protect it. There’s a cerebral quality to this book, but it never loses its heart. The family dynamics feel real, raw, and sometimes even gut-punching in their honesty.

The setting leans into covert ops territory think Cold War meets covert time manipulation, with strong CIA overtones and the occasional Agent Carter-style intrigue. If you’re into stories that make you think and feel, this one delivers. Hard.

What lingers most is the haunting idea of memory itself: who controls it, who erases it, and what happens to the truth when no one’s left to remember.

Final word: An unexpectedly moving, high-concept read that balances clever world-building with real emotional stakes. A definite four-star standout and the kind of book that stays with you long after the last page.

The Book of Lost Hours is one of the most original and moving books I’ve read in a long time. It completely transported me from the very first page. The story weaves together the lives of two girls, Lisavet in 1938 and Amelia in 1965, who are connected across time through a mysterious library filled with memories, history, and secrets that should never be forgotten.

The concept of the time space, a place where books hold the memories of those who have passed and can only be accessed with special watches, is absolutely brilliant and so beautifully imagined. It felt eerie, magical, and grounded all at once. I was completely captivated by Lisavet’s journey as a girl growing up surrounded by books and ghosts, and how she begins to understand the power of memory, truth, and storytelling. Amelia’s story is equally compelling, full of grief, determination, and wonder as she tries to unravel the mystery of her missing uncle and her family’s past.

The writing is stunning, so vivid and atmospheric. It made me feel like I was walking the halls of the memory library, hearing the whispers of the past alongside the characters. Every scene felt cinematic but never overdone. The pacing was perfect, with just enough mystery and emotion to keep me fully invested the entire time.

This is a story about time, loss, love, and how history is written and remembered. It made me think deeply about the stories we keep and the ones that are lost, and what it means to protect the people we love across the ages. I finished it with tears in my eyes and a full heart. I already want to reread it.

This book was excellent. I think that if you enjoy time-travel stories, this is the one for you. I enjoyed the complexity of the plot and the characters. There was excellent character development and depth of character.

An unforgettable novel follows two remarkable women as they navigate postwar and Cold War-era America, and the mysterious timespace —a library filled with books containing the memories of those who bore witness to history.

The story is fast-paced and well-developed. The plot is complex, as it jumps through time, yet feels consistent as it unfolds. The changes in the story kept me turning pages to find out what would happen next to each character.

I will highly recommend this book.

There were so many twists and turns in this book! I read it so quickly. It was really good. I really liked the suspense and mystery aspects of the book.

This book really surprised me! I didn’t know much going into it, other than the potential for time travel. I often pick up books with the barest amount of knowledge on what I’m getting myself into, and I am glad I did that on this one! There was lots of good suspense and surprising twists.

Lisavet is a young Jewish girl living in Germany as the Nazis are rising to power. Her father is a watchmaker, but more importantly, a watchmaker that can open the door into a place where time only exists in memory. One night, leading up to Kristallnacht, fearing for his daughter’s life, he puts Lisavet into the time space to wait while he goes in search of his son. But he never returns and Lisavet is left living in the time space for some 15 years.

Eugene works for the CIA in an organization that uses the time space to effect change in the world. The time space is home to books of every person’s, living and dead, memories. Agents from across the globe destroy these books in an effort to bring about change.

Lisavet meets Eugene while trying to save memory books. What remains of the story is one of love, deceit, betrayal and intrigue. I was rooting for their love story from the beginning! I hope you do too!

Thanks Netgalley for the eARC!