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!

This book is so beautifully imagined and created, with twists and turns and hints and loops that recreate reality and keep you guessing while you read it.

While I understand the obvious comparison to the setting of The Midnight Library, for me that's where the similarity ends. That book is focused on one person's regrets and decisions played out in an altered but familiar existence - this book is more of an international spy thriller, played out across human history and emphasizing what people will do for love.

This isn't a genre I usually enjoy, but I couldn't put this book down. I'm excited for it to publish soon so I can recommend it to my family and friends. Thank you to NetGalley, the publisher, and the author for the opportunity to fall into this time space a little early!

Wow! This book takes you on a rocky ride. Time travel or rather memory travels is an eye opener to a different realm of life. Heartbreaking and heartwarming read. Characters intertwine smoothly. Recommend this book. I was given an advanced reader copy of this well written book by NetGalley and I am freely sharing my review. #hayleygelfiso @authorhayleygefuso #simonandschusterpublishing @simonandschusterpublishing #netgalley @netgalley

I loved the concept of this story and found it so interesting. Are memories still memories after time passes and the memories are distorted in our minds? I do wish this unique concept had been a little more original in its exploration, but for a fast paced romantic drama, it did the job.

The relationships and family love are sure to captivate the hearts and imaginations of readers. This is a romance novel more than it is a time traveling novel. Which is great news for people who love romance, and maybe less exciting for those who prefer to time travel.

Mixed feelings. There were some really great parts of this book, and some not so great parts. For starters, I was able to guess the plot twists and reveals about 30% of the way through. Very predictable. The concept of a library of memory and time traveling is not new and The Book Of Lost Hours adds almost nothing new to the trope. I did, however, find the couple to be really enjoyable, their love story is what kept me hooked and interested. Was rooting for the couple the whole time. All the characters were either lovable, or the type you’d love to hate. The writing style is also a win, very engaging despite the predictability.

Thank you to NetGalley and Atria for the digital ARC in exchange for honest review.

I loved the concept of this book, and reading Lisavet’s arc in this story was heartbreaking and beautiful. I also enjoyed the parts where the characters were in memories but I wish the reader got to spend more time in these scenes to learn from the characters, instead of having all of the technical explanations before and after each time someone time walked. I feel like during the time walks was when the reader truly got to know the characters.

★★ ½

I'm finding that I'm such a sucker for time travel fiction. There's so much to say about how we choose what to commit to memory, and how our very selves are formed by it, that there's no shortage of ways it can be explored. The first half of The Book of Lost Hours gave us a set of unforgettable characters and a beautiful, lush time space that explored the idea of the tangibility of memories taken literally—and why those in power may seek to erase what they don't want the world to see. Being able to piece together the mystery of what really happened to Lisavet Levy through the multi-POV format was fun and engaging as a reader, and I loved how the distinct voices of the characters throughout the book went from distinct and bright to more muddied as their histories began to converge on one another. The romance was also spot-on (coming from someone that often doesn't read it!)—not forced, beautiful, and perfectly-devastating as Lisavet's and Ernest's sacrifices for each other only drew them deeper into tragedy.

However, I guessed one of the big twists of the story decently before it happened (which may have been intentional, but it still left me disillusioned), and the second half of the story felt soured to me—by a main antagonist that felt flat andcartoonishly-villainous (made even worse by exactly one [1] sentence of reflection that the author never revisited again), which stuck out like a sore thumb amongst the rich depth of characters that had been exhibited prior. This made me feel uncomfortably disconnected from what should have been a very emotional latter half and climax, and it instantly made the stakes seem fake and exaggerated—which left me waiting for the book to be over rather than able to enjoy an ending that I believe was executed perfectly despite the pitfalls concentrated within the 60-85% portion of the text.

I'll admit I'm not very good at suspending my disbelief, and readers that are able to do so more easily for the central conflict may find more fulfillment from this book. Until then, I will keep looking for a book that knocks the "memory library" concept out of the park—and I am deeply saddened that The Book of Lost Hours is not where my search ends.

Thank you to Atria Books and NetGalley for the ARC in exchange for an honest review. All opinions are my own.

I felt so much hope for this book! The premise was great...but it was too slow-paced for me. The reveal halfway through held some power (I wasn't able to guess it! so that was good) but it was the only spike of interest and excitement I felt throughout the entire book. As such, it's a 2.5 stars rounded up for me.

5/5

Wow. Just finished this book by Hayley Gelfuso and have already pre-ordered m a hard copy. Gelfuso seamlessly weaves a tale that defies time as we know it to exist. An unlikely love story, that delves into just how far one is willing to go for those they love.

I could not put this novel down, and found myself deeply invested in the characters and their lives. Gelfuso does an amazing job of invoking feelings in her readers - I loved immersing myself in her pages.

This story is genre-blending, part historical fiction, part speculative fantasy, with a dash of Cold War spy intrigue and a whole lot of emotional depth. It follows two women—Lisavet Levy and Amelia Duquesne—across different timelines (1938 and 1965), both connected by a mysterious place called the time space, a soaring library where memories are stored in books and accessed through special watches. It’s like The Midnight Library meets The Ministry of Time, but with its own haunting, lyrical twists.

What I loved: Lisavet’s arc is heartbreaking and beautiful. Trapped in the time space as a child, she grows up surrounded by other people’s memories instead of her own. Her journey is about reclaiming truth in a world where history is being rewritten by government agents.

Amelia’s storyline adds a layer of mystery and urgency. She’s pulled into the time space decades later to find a book her uncle Ernest once sought, and her discoveries challenge everything she thought she knew.

The writing is lush and immersive. Gelfuso’s prose is poetic without being pretentious, and the emotional beats hit hard. You’ll feel the weight of memory, loss, and love in every chapter.

The concept of timekeepers—agents from different countries manipulating history—is chilling and brilliant. It raises big questions about who gets to decide what’s remembered and what’s erased.
It’s not traditional time travel—it’s more like memory travel, which might surprise folks expecting sci-fi action.

Wonderful read, overall.

I don't believe I have read anything quite like this story. This was a beautifully complicated and heartwarming/heartbreaking tale. It is a true testament to how love can withstand the test of Time, how a mother will forever protect their child no matter the costs & that when governments get their hands on important things they will inevitably abuse it.

I thoroughly enjoyed this book and I have no doubt others will fall in love with the story the same way I did.

The Book of Lost Hours was everything I loved in The Ministry of Time mixed with The Library Trilogy with a splash of unique story telling and an intriguing plot. I loved the nonlinear storytelling that gives the reader breadcrumbs as we learn more about Moira, Amelia, and Ernest so as the big reveals happen, the audience is starting to connect the dots. I loved this story so much! I was enthralled the entire time and almost couldn't put it down. This is a must read for essentially anyone with eyes (or ears) to read with! I don't think I'm going to stop thinking about The Book of Lost Hours for a long time. You can ask my husband, I rambled extensively about it when I finished. The book isn't even out yet and I'm texting friends and family, telling them to buy this ASAP. I can't wait to gush more about this book on social media so please take my word for it, you're going to LOVE The Book of Lost Hours!

Thank you to Atria, NetGalley, and the author for allowing this early copy to be used for Camp NetGalley 2025!

Thank you to Netgalley and Atria books for this ARC in exchange for my honest review. I have posted the following review to Goodreads as of 07/15/2025 at the link provided below.

DNF at 30%

I immediately couldn't get invested in this book. It reminded me very very heavily of V.E. Schwab's The Dark Vault duology, the magic system is extremely similar. However, even though I adore V.E. Schwab that is my least favorite of her books. I think this set me up from page one of already not wanting to explore this concept, but I still stuck it out.

I just couldn't get into this story, despite my best attempts. I don't like or care about any of the characters, the story is unfolding very predictably and I feel like I could skip forward to the final chapter and find no surprises there.

I have read The Midnight Library and didn't particularly like it, but I don't see the comparison, personally. The themes are extremely different and the story is not the same at all. The only similarities are a library that's neither here nor there.

I think fans of The Dark Vault may enjoy this one since there's such similarities in the concepts of Timekeepers vs Keepers, Memories vs Histories, The Timespace vs The Vault, etc. But that just wasn't me this time.

Best of luck to Hayley Gelfuso and her future books!

A hauntingly atmospheric tale about grief, memory, and the passage of time. Gelfuso’s lyrical prose brings an eerie beauty to the story, perfect for fans of quiet fantasy with emotional depth.

This was an extremely creative and whimsical. A speculative fiction book that accurately compares to books like The Midnight Library, which I also loved, so I had to pick this one up. I am having a hard time avoiding spoilers, but this book is definitely one of those that is not only about the characters, but also about preserving history. I love the dual timeline, the romance, the fantasy of it, the world jumping within memories, really all of it. An excellent debut, and a consistent page turner for me.