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Dichronauts Hardcover – July 11, 2017

by Greg Egan (Author)
3.9 3.9 out of 5 stars 276 ratings
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Hugo Award–winning hard science fiction master Greg Egan returns with a new novel featuring one of science fiction’s most unusual worlds.

Seth is a surveyor, along with his friend Theo, a leech-like creature running through his skull who tells Seth what lies to his left and right. Theo, in turn, relies on Seth for mobility, and for ordinary vision looking forwards and backwards. Like everyone else in their world, they are symbionts, depending on each other to survive.

In the universe containing Seth's world, light cannot travel in all directions: there is a “dark cone” to the north and south. Seth can only face to the east (or the west, if he tips his head backwards). If he starts to turn to the north or south, his body stretches out across the landscape, and to rotate as far as north-north-east is every bit as impossible as accelerating to the speed of light.

Every living thing in Seth’s world is in a state of perpetual migration as they follow the sun’s shifting orbit and the narrow habitable zone it creates. Cities are being constantly disassembled at one edge and rebuilt at the other, with surveyors mapping safe routes ahead.

But when Seth and Theo join an expedition to the edge of the habitable zone, they discover a terrifying threat: a fissure in the surface of the world, so deep and wide that no one can perceive its limits. As the habitable zone continues to move, the migration will soon be blocked by this unbridgeable void, and the expedition has only one option to save its city from annihilation: descend into the unknown.
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  1. Print length
    312 pages
  2. Language
    English
  3. Publisher
    Night Shade Books
  4. Publication date
    July 11, 2017
  5. Dimensions
    6 x 0.97 x 9 inches
  6. ISBN-10
    159780892X
  7. ISBN-13
    978-1597808927
  8. See all details
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Editorial Reviews

Review

"Impressively bizarre . . . Egan may have out-Eganed himself with this one."—Publishers Weekly

"Egan (The Arrows of Time, 2014, etc.) specializes in inventing seriously strange worlds; this one might well be his weirdest yet."—Kirkus Reviews

"Hard science fiction in its purest form . . . Egan has always done the science half of science fiction as well as anyone can."—The 1000 Year Plan

"Per usual for Egan, conceptualizing the math and physics that form the foundation of this bizarre sci-fi tale takes some doing, but the results are well worth the effort."—B&N Sci-Fi and Fantasy Blog

“I always enjoy Greg Egan’s writing. Coupled with his scientific background and fertile imagination, he manages to come up with places and aliens unlike any others . . . not only does Egan offer a unique world and alien race – he also provides a cracking adventure story full of tension and excitement right from the start through to the climactic ending. . . . I love this one. Brilliant and inventive, this book reminds me all over again just why I love science fiction so much.”—Brainfluff, 10/10. Reviewed by Sarah J. Higbee

“I haven’t been this surprised and entertained by world building for a long time . . . the most brutal and poignant depiction of oppression I have ever seen in fiction. This is why I love Egan’s work – he is absolutely unflinching. . . . Like all of Egan’s work, Dichronauts is brilliant and sweet, heartbreaking and obscure.”—The Kingdoms of Evil

“I enjoyed this one very much—in large part because the characters and problems become very engaging as the story progresses, but also because I just liked messing around with the maths.”—The Oikofuge

About the Author

Greg Egan is a computer programmer, and the author of the acclaimed SF novels Permutation City, Diaspora, Teranesia, Quarantine, and the Orthogonal trilogy, all published by Night Shade Books. He has won the Hugo Award as well as the John W. Campbell Memorial Award. Egan’s short fiction has been published in a variety of places, including Interzone, Asimov’s, and Nature. He lives in Australia.

Product details

  • Publisher ‏ : ‎ Night Shade Books; First Edition (July 11, 2017)
  • Language ‏ : ‎ English
  • Hardcover ‏ : ‎ 312 pages
  • ISBN-10 ‏ : ‎ 159780892X
  • ISBN-13 ‏ : ‎ 978-1597808927
  • Item Weight ‏ : ‎ 1.15 pounds
  • Dimensions ‏ : ‎ 6 x 0.97 x 9 inches
  • Customer Reviews:
    3.9 3.9 out of 5 stars 276 ratings

About the author

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Greg Egan

Greg Egan

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Greg Egan lives in Perth, Western Australia. He has won the Hugo Award, the John W. Campbell Memorial Award, and the Japanese Seiun Award for best translated fiction.

Customer reviews

3.9 out of 5 stars
276 global ratings

Customers say

Customers find the story interesting and inventive. They describe the world-building as amazing. However, opinions differ on comprehension - some find the prose clear and easy to understand, while others find it difficult to understand the physics and world-building.

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Story qualityComprehension
9 customers mention "Story quality"8 positive1 negative

Customers find the story interesting and enjoyable. They appreciate the world-building and inventive storytelling.

"...His world building is the strongest and most inventive I have ever seen, taking place in alternate universes with fully worked out laws of physics...." Read more

"...ahead of anything I've read by any other author, and his world-building is stunning...." Read more

"Very interesting, especially the unorthodox geometry- would like to see more of this..." Read more

"...that are the basis of his books, different for each book, then they are enjoyable...." Read more

5 customers mention "Comprehension"2 positive3 negative

Customers have different views on the book's comprehension. Some find the prose clear and easy to understand, with few unnecessary sentences. Others find the physics difficult to understand and the world confusing.

"...of physics, visual-spacial skills, and a gift for math, much of the book is incomprehensible...." Read more

"...readers of Egan are used to - clear, succinct prose with very few unneeded sentences - so I would say that appreciating his previous work is a..." Read more

"Standard Greg Egan...meaning it's awesome. I had a harder time understanding the physics of this world than some of his other creations but nothing..." Read more

"...describes it with such patience and clarity that it is also impossible to misunderstand...." Read more

Top reviews from the United States

Nadia&Casey
4.0 out of 5 stars Amazing world and decent story
Reviewed in the United States on August 1, 2017
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I am a lover of hard science fiction and Greg Egan is the epitome of that genre. His world building is the strongest and most inventive I have ever seen, taking place in alternate universes with fully worked out laws of physics. The physics are typically one of the main focuses of his books with story and characters not quite as developed. He is no Mark Twain but rich prose and character development is not the main reason to read his books, I read his books to see the incredible ideas that no other author has yet explored.
6 people found this helpful
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pgcd
5.0 out of 5 stars World-building at its finest
Reviewed in the United States on May 28, 2017
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First off, the usual disclaimer: I believe Greg Egan to be the absolute apex in the "science" chain of hard science fiction - his ideas are always one (or a dozen) steps ahead of anything I've read by any other author, and his world-building is stunning.
"Dichronauts" is no exception: choosing to set a novel in a universe with very different rules from our own is a long and respected tradition but the care and depth of analysis you'll find here is not as common. Of course, since it's not a treatise but a novel, Egan had to take some (several) shortcuts - the protagonists are explicitly tasked to explore and explain their world, which leads to more pages of exposition than I'd probably like, and there are occasions when their inner monologue (or conversation) have a slightly off-putting "As you know, Bob" tone. On the other hand, without information like this the reader would have to spend half the time consulting Egan's webpage to understand what's going on, so I feel the tradeoff is more than justified. As a side note: I strongly recommend doing that anyway, because the images and animations in the site's section dedicated to "Dichronauts" are rather useful for those of us who cannot easily visualize the consequences of having two time-like dimensions.

From a "literary" standpoint, the style is pretty much what readers of Egan are used to - clear, succinct prose with very few unneeded sentences - so I would say that appreciating his previous work is a rather solid indicator of whether you'll like this one. The converse is also true, unfortunately: if you don't like his pragmatic approach to character development, or his tendency to veer off into scientific discourse when you least expect it, you probably won't like this.

One final note: in more than one page it's easy to read between the lines and find socio-political commentary on the issues and subjects that Egan has explored in the past: (im)migration, reaction to and acceptance of different cultures, self and personality and so on. Given the colossal differences between "Dichronauts"' universe and ours, though, it's rather hard to understand when that's a deliberate choice by the author and when it's just me projecting.
In other words, while it's tempting to read "Dichronauts" as a super-charged Flatland, I feel like that would be doing a disservice to both: reading it as a stunningly in-depth documentary set in a majestically ambitious thought experiment is probably the right choice.
40 people found this helpful
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Amazon Customer
3.0 out of 5 stars Interesting world, weak story
Reviewed in the United States on June 22, 2018
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I like how Egan can build a completely alien world by changing one fundamental law of physics. The bulk of the book is about showing you how many things work differently in this world compared to ours, with the story being almost an excuse to achieve this goal.

This is also the weakness of the book. Once Egan is done showing all the interesting parts of the world he built, the story just stops without resolving the main conflict. Maybe he's trying to set up a trilogy like he did with Orthogonal, but until a sequel comes, I can only judge the book on its own, as an unsatisfactory story.
7 people found this helpful
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EdLincoln
4.0 out of 5 stars Hard Sci Fi, Nearly Incomprehensible, Just Sort of Stopped.
Reviewed in the United States on September 8, 2017
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Greg Egan is one of the few people who still writes hard sci fi. This book is set in a world where certain fundamental features of physics are different. Unless you have serious knowledge of physics, visual-spacial skills, and a gift for math, much of the book is incomprehensible. The best part of the book was the exploration of life for a species with a sentient symbiote. Many major life decisions (like who to marry and what to do for a living) become different when you have a captive passenger. In the end the book just sort of stopped. The author painted himself into an impossible situation and lost interest in resolving it.
4 people found this helpful
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Daniel M. Bensen
5.0 out of 5 stars A Beautiful Book
Reviewed in the United States on August 3, 2017
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I haven't been this surprised and entertained by world building for a long time, and I was beginning to think I had outgrown science fiction. I hadn't. I just didn't know how far it could go.
The geometry of the world of Dichronauts is impossible to intuit, but Egan describes it with such patience and clarity that it is also impossible to misunderstand. Flatland lies somewhere at the base of this book, but Egan far surpasses anything Abbott managed, both in playing with dimensions and the most brutal and poignant depiction of oppression I have ever seen in fiction.
This is why I love Egan's work – he is absolutely unflinching. He never cuts corners with his world, his characters' motivations, or the agonizing dilemmas in which they find themselves. They are people trying to do right in circumstances in which doing right is physically impossible. They get no magic wands to wave, no convenient shortcut to everyone's best interests..
Like all of Egan's work, Dichronauts is brilliant and sweet, heartbreaking and obscure. Having read it, I feel like I have some tools to tackle the real world as well.
12 people found this helpful
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CFortC
3.0 out of 5 stars Fairly difficult alternate physics
Reviewed in the United States on October 8, 2017
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I am a long-time fan of Greg Egan's work and watch eagerly for his new releases. This one is another novel set in an alternate universe complete with alternate physics that the reader can enjoy puzzling out along with the plot. Or, the reader can usually turn to the back of the book for some explanation of the alternate physics.

Somehow, in the case of "Dichronauts" it just became too much for me. It might be my own fault - perhaps lacking the energy and/or perceived time to puzzle through the novel. But I still love the older Greg Egan body of work, some of which (e.g. Diaspora, Incandescence, many short stories, etc.) I've read multiple times over the years and expect to read again. But for this one, I've bumped into my limit at least for the time being.
10 people found this helpful
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Joseph Ferri
4.0 out of 5 stars science fiction, not science fantasy.
Reviewed in the United States on February 12, 2018
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Very interesting, especially the unorthodox geometry- would like to see more of this...
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Top reviews from other countries

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knolle
5.0 out of 5 stars Absolutely marvelous alternate universe story.
Reviewed in Germany on March 4, 2021
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Dichronauts is fantastic. Until about 2/3 into the book I thought it was the greatest adventure story I ever read. Only in the end it suffers a bit form Egans usual weakness: it just stops.

The story happens in another alternate universe, which clearly is Egans forte. After his orthogonal trilogy, which featured a world with four spacelike coordinates, dichronauts is the logical next step: a world with two timelike coordinates. Its fundamentals are worked out in far less detail than in the orthogonal series - probably because it is a far stranger setting. Even so (or because of this) the story bristles with surprise turns and is strange beyond measure. I don't want to give anything away, so I'll just say that it is mindboggling how otherworldly it feels. And yet, he managed to transfer so much of human thought and emotion - wonderfully twisted and adapted - to really make you think.

I loved this book and regret very much that it is not a few hundred pages longer.
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Mig Bardsley
4.0 out of 5 stars Very interesting, recommend reading the afterword first.
Reviewed in the United Kingdom on January 20, 2018
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Greg Egan can be relied on to present a view of a universe which is not at all like the one we're used to. So the dichronauts' universe has only two spatial dimensions but two temporal ones and I'm already lost. No matter, even though I hadn't read the afterword (which could helpfully have been a foreword) I was fascinated by the mundane detail of individual life and the larger ideas of whole communities over a bigger scale. I was also instantly engaged with the strange symbiosis of walkers and siders - people who (I think) could perceive in two directions, using their eyes, physically bonded with lizard/leech like creatures who could perceive in the other two directions, using 'pings' (would those be like bats' sonar?). The whole business of living like this sounds extraordinarily difficult and so it makes sense that the characters are quite good at getting on with each other - for the most part anyway - which makes them good company to travel with, through this very strange world.
This was not an easy read, in fact it was quite exhausting and, I imagine, would not attract non-sf readers much. But it was unusually interesting.
I criticised another of Egan's books, 'Clockwork Rocket' for over-indulgence in explanatory diagrams, however, in this book I imagine a few diagrams might have clarified some of the detail. I'm still struggling to imagine which way a head would be 'tipped' and where the pings were directed.
I'm hoping that the story will be continued. If there is a sequel, I shall certainly buy it; I would like to find out what happens to Seth and Theo and their companions and there is plenty of scope for future developments.
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FeydRautha
2.0 out of 5 stars Un Greg Egan raté
Reviewed in France on September 21, 2017
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Je n'avais pas imaginé écrire un jour une critique négative sur un livre de Greg Egan, mais il y a un début à tout.

Greg Egan, c'est le pape incontesté de la Hard SF, version très Hard. J'avais jusqu'alors toujours été passionné par l'incroyable ambition de ses écrits, sa vision éclairée d'un futur parfois proche, parfois plus lointain, sa maîtrise des concepts scientifiques et mathématiques les plus avancés, même si l'aridité de son style pouvait parfois rendre la lecture de ses romans et de ses nouvelles quelque peu singulière. Greg Egan écrit parce qu'il a des idées, scientifiques mais aussi parfois politiques, à partager de façon pressente, et pas pour proposer un moment de détente à son lecteur. Ses écrits réclament un engagement de la part du lecteur, une attention et une réflexion. Ainsi que bien souvent des connaissances en sciences et en mathématiques assez solides.

Mais voilà, j'ai eu beaucoup de mal à finir Dichronauts, par manque d'intérêt pour le monde décrit et l'histoire contée. Dans ce nouveau roman, Greg Egan reprend l'idée explorée dans la série Orthogonal d'un monde régit par des dimensions de l'espace temps différentes de l'univers que nous connaissons, où il imaginait un monde répondant à la métrique de Riemann, dans laquelle les trois dimensions de l'espace et celle du temps sont strictement équivalentes, pour faire court. Le propos des trois romans de cette série était alors d'explorer les conséquences de cette métrique. Cela fonctionnait car au niveau le pus bas, il avait finalement peu de différences entre cet univers et le nôtre, et il était facile pour le lecteur d'évoluer dans ce monde sans trop perdre ses repères.

Greg Egan complique les choses dans Dichronauts en imaginant un univers où il n'y a non plus 3 dimensions de l'espace et 1 du temps, mais 2 dimensions spatiales et 2 temporelles. Cela donne un univers à la géométrie hyperbolique. Et le soucis d'une hyperbole, si vous vous souvenez de vos cours de math, c'est qu'elle diverge aux extrêmes. Il ne s'agit pas d'un roman de science fiction, mais d'une fiction mathématique. Les habitants de ce monde sont des symbiotes, constitués d'une paire d'individus, soit un "walker", dont on ne sait trop quelle forme il a si ce n'est qu'il marche sur deux jambes et qu'il possède deux bras et une tête, et un "sider", sorte de sangsue logée dans le crâne du walker. En raison de la géométrie hyperbolique de ce monde, la lumière ne se propage pas de la même manière dans toutes les directions. Un walker ne peut ainsi percevoir le monde que dans une direction. En utilisant l'écholocation, le sider lui fournit une vision dans l'autre direction. Mais ce n'est pas tout, le walker ne peut tourner sur lui-même, car sa forme géométrique divergerait rapidement, jusqu'à le briser. Il est ainsi condamné à la naissance à faire face à l'ouest ou à l'est. Pour se déplacer vers le nord ou vers le sud, il doit faire un pas de côté. une chute dans la mauvaise direction, et c'est le drame. La simple manipulation des objet est aussi compliquée voire rendue impossible par cette géométrie. Greg Egan va prendre le prétexte d'une exploration du monde par quelques individus pour s'amuser avec cette géométrie particulière et en tester les conséquences. C'est sans doute amusant pour l'auteur mais nettement moins pour le lecteur.

Le problème principal qui se pose au lecteur est l'impossibilité de se représenter ce monde, les mouvements, les déplacements, la physique de base de cet univers. Le mal de crâne est rapide, et le désintérêt prompt. Greg Egan n'a jamais brillé par le développement de ses personnages, mais dans ce cas, ils sont totalement inintéressants. L'histoire elle même n'est pas plus enthousiasmante. Au final, ce que me gène le plus, c'est qu'il y a de trop nombreuses impossibilités conceptuelles dans un tel monde pour rendre sa description un tant soit peu crédible voire même simplement amusante. Je n'ai eu de cesse durant ma lecture de me dire que l'évolution sous de telles contraintes, n'aurait pas abouti aux créatures ni au monde décrits par Egan dans ce roman. Elle n'aurait d'ailleurs abouti à rien. Greg Egan fait le choix de ne pas envisager les conséquences de la géométrie hyperbolique au niveau microscopique. Mais les conséquences sont les mêmes qu'au niveau macroscopique : une simple molécule ne pourrait exister dans ces conditions.

Au final, si j'ai trouvé ce roman très ambitieux, je l'ai aussi trouvé raté car ennuyeux, et pénible à lire de part la difficulté, voire l'impossibilité, à se représenter mentalement ce monde. Le plus mauvais Egan que j'ai lu.
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BumblebeeTheMighty
5.0 out of 5 stars Loved it!
Reviewed in Germany on February 18, 2023
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Finally a science fiction book that really challenges your imagination. This is exactly what I’ve longed for. Five stars plus!
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Ulrike
5.0 out of 5 stars selten hat mich ein Buch nach dem Lesen so lange beschäftigt
Reviewed in Germany on September 26, 2017
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Ich möchte gar nichts über den Inhalt sagen, nur so viel: ich war auf jeder Seite geflasht. Wie kommt man darauf sich so ein Universum vorzustellen!?
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