Alastair Reynolds is best known for his long novels and the complex future history which builds from the first, Revelation Space; book buyers have seen little of his short fiction. Much of this work was published in British magazines such as Interzone and the short-lived but wonderful Spectrum SF. Now readers have a chance to catch up on most of Reynolds's shorter writing, with the appearance of both Galactic North, which collects his Revelation Space stories, and Zima Blue and Other Stories, which contains much of the rest of his shorter output. Of the eight stories in Galactic North, three are previously unpublished and illuminate the future history of which they are a part (without turning the collection into a fix-up). Nine of the ten stories in Zima Blue have appeared previously.

The Revelation Space universe is a setting where humanity has reached out across the void, in long, narrow spaceships that approach the speed of light. We have also split into clades such as the Conjoiners, who have taken on a form of machine-mediated hive-mind, and the Ultras, who crew and control the spaceships. As they expand into the galaxy, humans encounter remnants of alien life and, in due course, the Inhibitors, who soon develop into a nemesis. Reynolds tends to focus on the darker corners of his characters and their environments, building a grandiose, gothic flavour over a hard science fiction base. This future history is relativistically bound, and the stories in Galactic North are ordered in the book to fit their internal time line. However, time lines can be difficult things—in his first novel, the puzzle of getting the separate time frames to mesh is a significant component of the book. This is not unusual; Reynolds is clearly a lover of puzzles, perhaps even more than of future histories. Many of the stories collected in these two volumes have a trick at their heart, a revelation that reshapes what has gone before. When reading the stories close together, however, an expectation of inversion builds up, so the repeated motif of revelation becomes something of a disadvantage; the reader subconsciously starts to plan against it. This is quite apparent in Galactic North, in which every story ends with a twist.

Many of Reynolds's stories also possess a sense of scale. They tend to be long—and longer still as his career has progressed—but more than this, they do not flinch from gazing on the immensity of the universe. In "Understanding Space and Time" (2005), from Zima Blue, vast time periods are summed up with the line "Hot blue stars formed, lived and died while he gnawed away at the edges of certain intractables" (252). The story is of the last human and his quest for a deeper understanding of the universe, aided by an avatar of Elton John. It is, at heart, whimsy, but Reynolds's familiarity with the big questions of physics and the huge distances of space and time enable him to mix in some sense-­of-wonder. Reynolds's former career in astrophysics surely means he could write a much more difficult piece about understanding space and time, but he would much rather show us infinity.

Showing such vastness is simpler within the Galactic North stories, as the framework of relativity is clearly established. In "Weather" (2006), for example, a spaceship is crippled between the stars, caught at a quarter of light speed—too slow to get anywhere useful in a human life span but too fast for its passengers to get off even should they reach their destination. The final, title story, "Galactic North" (1999), is an archetypal example of SF staring at infinity. Not coincidentally, the piece is littered with all the worst faults and best values associated with hard science fiction. The characterisation is barely adequate to drive the plot in the right direction, but Reynolds wants to evoke deep time here, and he does that magnificently. The opening section describes a sophisticated highjack of resources that sets in train a relativistic chase across the galaxy and, thereby, across time. Reynolds then drops his protagonists into events across thousands of years, giving a snapshot view of grand swathes of future history. "Galactic North" also displays the disintegration of the common frame of reference over such vast distances of space and time. In Revelation Space the puzzle was how all the characters could be in the same place and time; in contrast, this story demonstrates how far out of synch it is possible to get. It also offers a whole new level of threat to human survival and suggests that, over enough time, even a galactic culture can be destroyed by its own mistakes. All this and a shockingly bad pun make up for the lack of affect in the plot itself.

It is rather rare, though, that Reynolds's characters are so thin. Galactic North opens with two Nevil Clavain stories that turn almost wholly on the nature of Clavain himself. The man is central to Redemption Ark (2002), and here we have his origin story. He begins as a negotiator from base humanity on his way to speak with the major Conjoiner group. The Conjoiners are bottled up on Mars, feared and abhorred, but Clavain still recognises an essential humanity in them. "Great Wall of Mars" (2000) repeatedly offers Clavain the choice of death or compromise, and each compromise draws him closer to the Conjoiners. But more than a tale of joining the transenlightenment, this is Reynolds flexing his writing muscles, getting an early block of his future history down on paper. Given that he was already a couple of novels into the series, this might have seemed an urgent task, but the story has a light touch. Perhaps Reynolds enjoyed the chance to slip backwards, away from the baroque future inhabited by the Inhibitors. From the perspective of Clavain's character arc, the most important elements of the second story—"Glacial" (2001)—are his gradual integration with Conjoiner society and the "awakening" of his proxy daughter from the machine realm to the human. However, as with any independent episode of a long-running series, there is also a foreground story. In this case, a group of Conjoiners is trying to understand the failure of an early human base on an icy planet. The solution has a satisfying combination of human and natural elements—and also leads Clavain to a new stage in his Conjoining. I read both "Great Wall of Mars" and "Glacial" when they first appeared in Spectrum SF and thoroughly enjoyed them. Since then, I've read Bruce Sterling's Schismatrix. Reynolds clearly states his debt in the afterword to Galactic North—"Schismatrix . . . will melt your face" (342)—and it is remarkable how differently this story reads in the light of Schismatrix. These stories do not sparkle less knowing their heritage, but an element of homage becomes apparent. It is interesting that there is so little resemblance to Charles Stross's Accelerando or his Singularity space operas, despite being written at about the same time and sprouting from the same branch of SF. I suspect this has a lot to do with the authors' pre-writing careers—Stross the computer geek versus Reynolds the space nerd. Reynolds's Revelation Space universe has no room for an AI singularity, even though the Conjoiners are a machine-mediated hive-mind.

Nor is there any sign of a godlike artificial intelligence in the assorted stories in Zima Blue, although there are occasions when machine minds arrive at consciousness, such as the thoroughly entertaining "Spirey and the Queen" (1996) and the thoughtful "Zima Blue" (2005). The former is an action story with philosophical questions at its core. A centuries-long war is being fought in the Swirl, a solar system still coalescing into distinct planets. The two human forces are vastly separated, so the combatants and weapons are machines, continually upgraded by their human maintainers. When a senior officer learns the machines are not quite the tools they are thought to be, her fellow humans order her death. Both the constraints of ship-to-ship combat and the settings possible in a loose accumulation of planetary material are cleverly used to define the shape of the story, whilst the underlying ideas about human—and nonhuman—nature turn the plot through several somersaults without ever losing pace. By contrast, "Zima Blue," another title story concluding its collection, is written in the voice of the journalist Carrie Clay. Mixed in with the story of an artist who becomes obsessed with a specific shade of blue is a meditation on the definition of character and how each of us changes or petrifies over time. This is a story that bears repeated reading—and knowing the punch line meant that I more clearly noticed the quality of the rest of the writing—an experience that reflects the piece's themes beautifully.

"Zima Blue" is linked with the book's opening story, "The Real Story" (2002), by the journalist central character, and they are amongst the two or three stories that allow the possibility of faster than light travel. This weakening in Reynolds's physics standard is obscured by handwaving that the FTL is alien technology. Such technology enables Reynolds to use different story elements—spaceships gather from across the galaxy for an art event in "Zima Blue"—but he doesn't really tell a different kind of story. It is almost as if he doesn't want to draw attention to his having broken his own rule. Perhaps there is FTL in "Beyond the Aquila Rift" (2005), but it isn't fast enough to close down the size of the galaxy by much. Within a few pages, the story builds from a "routing error" of a few days to the realisation that that the characters have travelled so far beyond their local domain that the whole culture in which they were born must have disappeared.

"[The transport network] used to span the Galaxy," Greta said. "Then something happened. Something catastrophic, which I still don't understand. A shattering into vastly smaller domains. Typically a few hundred light-years across."

. . .

"We've come a lot further than a few hundred light-years." (50)

An alien network that crosses vast distances is important to "Hideaway" and "Merlin's Gun" (both 2000), which both concern the life of the second story's title character, a human in a galaxy where alien cyborgs relentlessly destroy our kind. There is a neat bit of wordplay here, naming all the characters for birds, so "Merlin" is not an exceptional name within the context. Of course, our own awareness of Arthurian myth affects the name's impact, as it surely is intended to, particularly when the man has become a legend within his own society by the time of the second story. "Merlin's Gun" is one of the highlights of Zima Blue, playing with perception as we casually trot across millennia of time and space to seek out a weapon made by ancestor cultures. The story is a two-hander, and both characters are strong and well-defined, in turn cooperating and competing. As a bonus, there is a joke that readers should get but, as with Merlin's own name, the characters are never intended to recognise. By contrast, "Hideaway," written as a prequel—and placed earlier in this volume—is deathly intense, overlong for its plot, and heavy on the world building and political interaction of people and groups it is difficult to identify with.

This weight of worldbuilding is also a problem with "A Spy in Europa" (1997), written as Reynolds was defining his Revelation Space history. The spy in question is from one of the societies in circum-Jovian space, and the tale is a cold war story bent by personal agendas, but it tries to do too much in the word count available. Reynolds likes room to move, and it seems he was also trying to give shape to his universe. The location and nature of the competition between societies have echoes of Sterling's Shaper/Mechanist universe, but Reynolds's societies show a greater love for engineering themselves to suit the planets they find than staying out in orbit in the manner Sterling's peoples chose. The unlikeable first-person protagonist is well drawn. Confident that he is the smartest, he is unable to recognise the extent to which he is being manipulated by both his own side and his Demarchist enemies. His encounter with the Denizens, genetically engineered creatures of the cold Europan seas, does not go well. "Dilation Sleep" (1990), written far earlier, is a particularly interesting addition to the Galactic North collection from an archaeological point of view. As Reynolds says in his afterword, it doesn't really fit. The Revelation Space universe didn't quite exist when he wrote this story, but the Melding Plague has already hit Yellowstone, a key setting for his second novel, Chasm City (2001). Here, escape from that plague provides the story's context, while the plot is typical of the series, involving a dark, haunted spaceship, indentity confusion, and a disastrous interface between human and machine. There are also black, blocky three-dimensional shadows, imagery reused in the novels as Inhibitors. There isn't much call for character in this mood piece.

By contrast, Reynolds uses subtle character portraits to drive the moods in Zima Blue’s "Signal to Noise" (2006). The author employs the many-worlds theory cleverly, particularly the idea that the moment of contact with an alternate defines the beginning of divergence. The tale told on this framework is of a temporary transfer to another universe which allows the protagonist to spend time with another version of his suddenly dead wife. The husband is well drawn, indecisive yet suddenly driven to compromise his principles. The nature of the technology used to make the transfer means he finds himself gradually slipping away from the world where his wife survives. At first glance, the story is rather mawkish, but this is largely due to Reynolds's success in separating the practical responses of the surviving couple from the helplessness of the loner.

"Signal to Noise" is the sole new story in Zima Blue, while three of the eight stories in Galactic North are seeing their first publication. All three build on existing lore, but only "Weather" takes the opportunity to reshape something of the world that Reynolds and his readers know. Out of the central current of his own history, Reynolds is able to expand on Conjoiner lore, the war on Mars, and the nature of the Conjoiner Drives, which enable human space travel to approach light speed. This last is a great payoff for longtime readers. I can imagine it will also have interesting reverberations for those who move on to the novels from here. The more subtle twist helps make this my favourite story in the volume. "Grafenwalder's Bestiary" is a pleasant indulgence for those of us familiar with all that has gone before, with echoes from Chasm City, the novella Diamond Dogs, and hints at the survival of the Denizens from Europa. Like "Dilation Sleep" and Chasm City, it turns on the central character's definition of himself. "Nightingale" also returns to a setting from Chasm City. This reuse of setting increases the cramped feeling of the Revelation Space universe, the implication that there are limited habitable systems out there. There is wonderful imagery in this story, decorating a rather simple plot about the care with which a witch makes promises, even when the witch in question is a gamma-level artificial intelligence controlling a hospital ship in space.

The two volumes differ in more than their separation of the Revelation Space stories from the rest of Reynolds's writing. Zima Blue has a rigorous copyright page detailing the first publication of each story, whilst Galactic North does not bother with such information, although Reynolds makes his relationship with Interzone clear in the afterword for the book. This afterword gives the author the chance to write a decent essay about his work, with a safe assumption that the reader will, at the least, be familiar with all the stories in this book. Reynolds reveals more about his influences than most readers would guess from the works alone, sharing his enthusiasm for other writers and for both his former career in astrophysics and his current life as a writer. For Reynolds fans who didn't see it in a recent Locus, this piece is worth the book's cover price alone. Being in the form of an essay, it says more, and reads more coherently, than introductions or afterwords to individual stories normally manage. Zima Blue instead takes the route of brief afterwords to each story, which perform the different duty of better locating the stories in the time line of the author's own life. The backbone of Revelation Space makes Galactic North a stronger, more even collection, but the best individual story amongst the two collections is "Zima Blue." Readers who have enjoyed the Revelation Space novels are likely to leap at Galactic North, but Zima Blue and Other Stories gives a better feel for Reynolds's short-fiction career and the breadth of his interests.

Duncan Lawie has just moved to the Kent coast and now thinks he will have time to read all the books on his shelves. His work also appears in the Zone.