"The Underworld" is a fantastic book for people who love earth sciences and adventure nonfiction. Author Susan Casey makes the salient point that deep sea exploration is just as (if not more) relevant, important, and soul-stirring as going to space.

Casey takes us deep under the waves to look at the weird, wild, wonderful creatures who thrive under enormous pressure and help absorb the planet's carbon dioxide. She also details the quirky individuals (sea cowboys?) who travel to the bottom of sea trenches to explore worlds never before seen by human eyes. You've got scientists, corporations, and billionaires jockeying for position to not only research the deep sea but potentially exploit it as well. Sometimes both.

A riveting read that will leave you awed.

I have never stopped to google things while reading a nonfiction book as much as I have while reading ‘The Underworld’ by Susan Casey. I don’t have much of a knowledge base for deep sea aquatic life, so I was blown away by the vast array of animals of all shapes and sizes that were featured in this book (see the photo inserts for some truly wild deep sea creatures and definitely google the rest).

Part travelogue, part scientific treatise, part call to arms, ‘The Underworld’ is full of interesting histories on deep sea diving and manned submersibles, all the while reminding the reader that the seas in question are facing existential threats from us humans.

The true depths of the seas are still very much unknown to scientists. Even though they are right below us, most financing and interest has been in the stars rather than in the seas; however, as Casey writes, “to meet the deep is to have your beliefs recalibrated, your perspective permanently tweaked.” My perspective has definitely changed and I have this book to thank.

The Underworld is a blend of deep ocean exploration history and travelogue while also advocating for both exploring and protecting our oceans. Part of the book is spent on the changing views of life in the ocean as well as how technology developed to be able to finally explore so much uncharted territory. Another part focuses on Susan Casey's own deep dive and the various events that led up to it. The last part tackles the important issue of protecting the ocean environments from exploitation and learning more about how the deep ocean functions. Overall, a well-written and timely book about a part of the natural world that is still vastly unexplored and yet critical to the health of the planet.

An exceptional book! Such an amazing world that has been for so long overlooked. Thank you, Susan Casey for sharing your adventures and insights. Ms Casey is a wonderful writer. She really captures one's attention and doesn't let go. I will be following up on her suggestions of ways to help protect the depths of the ocean. Thank you for bringing its importance and fragility to my attention in such an engaging way!

I'm not the only one who was interested in the Titanic submersible that exploded, so this was a a timely read. It offered lots to think about especially in how all other submersibles are round for a reason which seems to be an issue with the recent wreck. I didn't know hardly anything about undersea mining which was enlightening and terrifying.

Susan Casey is known for her previous books, among them “The Wave: In Pursuit of the Rogues, Freaks, and Giants of the Ocean,” and “The Devil’s Teeth: A True Story of Obsession and Survival Among America’s Great White Sharks.” In her new book she continues exploration of the ocean and tells the readers about her adventures in the depth of the ocean and history of ocean research over the last two hundred years . Reading the book you will learn that abyss, twilight zone, sunlight zone, all these terms have a separate meaning related to the ocean depths. But these do not describe the depth of the ocean rarely visited even by explorers. Deep ocean is “defined as the waters below six hundred feet which cover 65 percent of the earth’s surface and occupy 95 percent of its living space.” Susan Casey postulates in her book that our survival depends on the ocean research as. It helps us learn about climate, past and future. She says that the space is much more explored than the ocean. She calls the ocean “an earth’s haunted basement.” And what treasurers one can discover there under Susan's guidance! Do you know that “In the deep, there are creatures that breathe iron and creatures with glass skeletons and creatures that communicate through their skin?” Susan travels all over the world chasing the deep and delivers fascinating story.

I should start by saying I got a free copy of this book from NetGalley (who immediately erased my epub when I scrolled to the last page, so lesson learned: if you want to review your notes and highlighting before a book is archived, it's best not to go all the way to the end [there's a submersible joke in there somewhere, I just can't find it]).

I requested the book on NetGalley because I've read some of Casey's journalism and really admire her work on the ocean. Her writing is engaging and her narrative -- both her voice and the structure of the story itself -- is entertaining and immersive (pun not actually intended but welcome). That said, what started pretty slowly blossomed about a third of the way through into a gripping tale of undersea adventures, deep-sea marine biology, and spiritual thoughts on the meaning of our largest unexplored frontier. There is lots of good data on the breadth and climatological significance of the deep in this book but, again and alas: NetGalley took back my epub before I could copy any of those beautiful facts and astonish my one or two readers here with my second-hand erudition.

One thing I will say about this book is that the timing of its release -- for better or worse -- couldn't be more on-the-nose. I, like many folks, watched the horrifying news cycle about the search for the "lost"* Titan submersible, which of course opened up a whole new cultural browser tab on the submersible industry: who submersibles are made for, what they do, how they're different from submarines, why they're so expensive, who is actually doing the dives, who makes them, why we as a society cared more about the disappearance and rescue of five people than the hundreds of refugees who died that same week one ocean away, etc. This book is actually a fascinating look at what is apparently a robust and generally safety-obsessed industry (OceanX -- the now-defunct company that owned the doomed Titan -- gets I think only one mention FWIW; likewise, Casey has a brief -- but, in retrospect, haunting -- conversation with Paul-Henri Nargeolet, the Titanic expert who died on the submersible). It is an industry that knows that the best way to change hearts and minds about plans to mine the deep for rare earth minerals (bad, bad, really bad idea) is to come back from the hadalpelagic zones bearing gifts of science: maps of the fascinating topography of the ocean floor, images of the real-life alien creatures that populate the darkness, and stories of the universe of unknown, unnamed**, and unexplored life lying at the bottom of our own planet. It's an endeavor Casey tells with hope, warmth, humor, and -- where it's called for -- justifiable outrage at the irresponsible gold rush by mining organizations to strip what in other circumstances have been identified as the shared heritage of all humankind.

In short, if you're looking for a great story, read this book. If you're looking for more information about the exploration of the deep, read this book. If you're looking for great prose about the beauty and fragility of the ocean, then read all Casey's books, but especially this one.

*Lost is in quotes because [spoiler] apparently the U.S. Navy knew minutes after it happened that it had imploded.

**Actually, some of the creatures have names that speak more to their weirdness than their actual taxonomy. Case in point: the weirdfish.

Thank you NetGalley for the ARC! I have long been obsessed with the ocean, so I knew I had to read this one, and I'm so glad I did because it was incredible! Susan Casey takes us on an expansive exploration of some of the major players, the scientific discoveries, the weird but incredible marine life, the geology that encompass what the deep ocean is. She also touches upon things that threaten our deep oceans and planet - climate change, deep sea mining, etc. This book was so fascinating that I found myself unable to put it down. I would recommend this to anyone!

I must begin this review with a warning. Reading this book will turn you into an unstoppable well of horrifying/weird ocean facts. Depending on your friends--this may or may not kill at parties. I don’t go to parties, but my boyfriend suffered through three days of me reading whole paragraphs of this book out loud to him because I needed someone else to know the cool facts I was learning. This is a “I can’t shut up about this book” book. I can say it’s one of the best non-fiction books I’ve read so far this year, and it may end up topping that list when I make it in December.

You may think you know the ocean--cruising along the top in a boat or a kayak, sunning yourself on the shore, maybe scuba diving if you’re one of my more adventurous and outdoorsy friends. But this is the ocean as you have never seen it before. As with all immense natural forces that shape the ecology we live in, the ocean is larger, deeper, weirder, and more terrible than you have imagined.

Susan Casey is a masterful tour guide. At the beginning of the book, as she gushed about her love for the ocean, I thought that she maybe had a few screws loose. By the end I was trawling through the bibliography of the book to try to find more books about the ocean. Casey will make you fall in love, as you see the ocean through her own eyes.

Casey has smartly not ignored the people who have become enchanted by the deep. Her book is populated with characters whose bios seem made up. Like any insular scientific community, the scientists who specialize in the deep sea are larger than life, and, as Casey profiles them, impossible to forget.

If you love nature at its purest and most awesome, if you love grand stories of scientific discovery, if you love state of the art submarines, this book is a can't miss event for you. Thank you, Susan Casey, for allowing me to recapture the wonder and obsession of the ninth grader who read an article in National Geographic about what happens to whale carcasses when they fall to the sea floor, and proceeded to write her bio term paper on Whale Fall. I truly believe there’s something in this book for everyone

I received an advance copy of this book in exchange for this honest review.

This book should win awards and I don't say that often.

I've just finished the ARC of "The Underworld," a nonfiction exploration of what we know of the deep sea, how we know it, and in what ways we are actively threatening that delicate ecosystem.

What I can't get over:
The author's writing ability. Expertise is making something look easy, and by God, does Susan Casey's show that. She has a gift for writing in a way that is informative, illustrative, and yet incredibly vibrant--like listening to a friend. She writes that a wreck was "smeared" across a coastline, that kicking up orange sentiment was like a cloud of Cheeto dust. Reading her writing is the linguistic equivalent of falling onto a very plush bed--so good that is positively decadent.

The writer's ability to make what might seem a static point (the ocean is wildly unknown to us and packed with creatures and creations beyond our imagining) dynamic and engaging. If you're reading this book, you're likely very inclined to the points the author makes (pro-nature, pro-science), but it isn't boring at all to stay in this world. I genuinely loved it.

Finally, "The Underworld" is also an homage to the scientists and explorers who are pushing our worlds of knowledge. In a world where we've recently seen the dangerous impact of profit-driven idiots ignoring scientists and the power of the deep, it's a joy to see the respect given to expertise here.

With extreme gratitude to Netgalley and the publisher for allowing me to read an ARC of this book in exchange for an unbiased review.

This is how you write non fiction. I felt like I was there every step of the way. Casey has a gift for narrative non fiction that is matched by few. I can’t wait to get my hand on her others works.

5 stars

Susan Casey has written a masterpiece on human exploration of the deep ocean. This meticulously researched, engagingly structured, passionately written book is an absolute joy to read. Casey details the history of mankind’s relationship to and exploration of the deep ocean, travels around the world to speak with recent explorers, biologists, engineers, and thrillseekers, and ultimately takes her own deep dive in a manned submersible to the ocean floor. At all times she emphasizes the awe and reverence that the deep inspires, and the necessity of that human element, of the wonder of actually seeing the deep ocean in person (rather than through robot-gathered data) in driving conservation and respect for the ocean floor.

The book focuses on the abyssal and hadal zones of the ocean, which occupy 60% of the earth’s surface but remain mostly unmapped and unknown. Previously considered to be a barren wasteland, this region is actually teeming with biodiversity and may hold the secrets to the origin of life on earth, and few things are more exciting than reading Casey’s breathless descriptions of the wonder and mystery to be found there.

Part well-explained science writing, part adventure story, part impassioned plea for conservation of our planet’s largest environment for life on earth, Susan Casey’s <i> The Underworld </i> is a sensational read for absolutely anyone with so much as a whisper of curiosity about the deep ocean.

The depths of the ocean have been misunderstood, miscalculated, but mostly, unknown. For centuries humans have hypothesized what lies at the bottom of the ocean conjuring up horrific images of sea monsters thirsty for destruction. We have long since known more about the far reaches of space than the depths of our oceans. Susan Casey takes you along on her journey with the scientists attempting to get to the bottom of it (pun intended) and to make discoveries that will change everything we know about our planet. She seamlessly transitions between the history of deep-sea exploration and her fascinating experiences aboard research vessels lacing the urgency of climate change action with the beautiful and mysterious world that lies miles below the crashing waves.

Prepare to be both horrified and mesmerized by the ocean in Susan Casey's, "The Underworld."

As a rule, I am not a fan of deep dark places which seem to have no end. My phobia was only reinforced by chapter 2 of this book which reads like a horror story. Casey chronicles the first deep sea dives and the reader can feel the claustrophobia along with at least 2 other phobias. I have never been more excited to be on land and not stuck in a cramp, cold, and damp sphere.

Nightmares aside, this book is excellent. Casey mixes the history of ocean exploration with her own modern day adventures. Casey is a great storyteller, but what truly makes this book special is her love of the ocean. It is palpable on every page and her excitement is infectious. I loved this book and even if you don't necessarily like the ocean or science, Casey will make you a convert.

Oh, and there are also ridiculous fish names. Did you know there is an assfish? Because there is an assfish.

(This book was provided as an advance copy by Netgalley and Doubleday Books.)

I'll read anything by Susan Casey, and when I discovered that her next book would be about the deep sea...well, let's just say I've been checking NetGalley on the daily for months now. Because I already read a lot about the deep sea (including Laura Trethewey's The Deepest Map, which also follows the Five Deeps expedition), this book occasionally felt less revelatory than some of her others -- but her unique combination of vivid writing, passion for ocean conservation, and personal engagement with her subject matter made this well worth a read (and, I'm sure, eventually a re-read). Highly recommended to fans of Rose George, Mary Roach, and James Nestor, or anyone who just loves the ocean!

Many thanks to the author, publisher, and NetGalley for the opportunity to read and review!

Spectacular

The Underworld by Susan Casey is a stunning example of narrative nonfiction at its absolute best. Casey mixes memoir with history, taking us along her adventures to the deepest parts of the ocean. This is a highly scientific and technical subject, but she spins literary magic with her beautiful prose, making it delightful and easy to read. It took me longer than usual to read, because I was constantly googling photos of deep water creatures, and stopping to watch documentaries on deep sea exploration. I often found myself highlighting sections due to their lyrical beauty and wisdom; on a sentence level the writing is a treasure trove of quotes to keep and re-read.

You will learn about the history of deep sea exploration, the people who pioneered this area, the machines they invented, the underwater worlds they have discovered… and the importance of this still unknown part of our world.

The best literature not only educates and entertains, it also changes us. After reading this, you will be in awe of the deep ocean, and will want to protect it. I learned so much from reading The Underworld and I rank it as one of the best non-fiction books I’ve ever read.

Thank you @NetGalley and @doubledaybooks for letting me read this in exchange for an honest review.

Pub date: 1 Aug 2023

I absolutely loved reading this book. I was completely drawn into the topic and could not stop reading it.