Xeelee Sequence
The Xeelee Sequence is a series of hard science fiction novels, novellas, and short stories written by British author Stephen Baxter. The series spans billions of years of fictional history, exploring humanity's future expansion into the universe, its intergalactic war with the Xeelee, a supremely advanced Kardashev Type V alien civilization, and the Xeelee's own conflict with dark matter entities known as Photino Birds. The Xeelee are described as symbiotic entities composed of spacetime defects, Bose–Einstein condensates, and baryonic matter.
Overview
As of August 2018, the series comprises nine novels and 53 shorter works, including short stories and novellas. All are set within a fictional chronology that spans from the Big Bang to the eventual heat death of the universe and the singularity portrayed in Timelike Infinity. An omnibus edition of the first four novels, entitled Xeelee: An Omnibus, was released in January 2010. In August 2016, the entire series of novels and stories was released in a single e-book volume, Xeelee Sequence: The Complete Series. Baxter's Destiny's Children series is also part of the Xeelee Sequence.Conception
Baxter first conceived of the Xeelee while writing a short story in the summer of 1986 as a hobby. He introduced powerful off-stage aliens to explain the story's titular artifact. In developing the backstory, he began to outline the elements that would later define the Sequence: a universe populated by intelligent species living in the shadow of the incomprehensible Xeelee.Setting and Themes
The series introduces several notable species and civilizations, including the Squeem, a group-mind aquatic species; the Qax, whose biology depends on the interactions of convection cells; and the Silver Ghosts, colonies of symbiotic organisms encased in reflective skins.Several stories explore humans and posthumans in extreme environments: at the heart of a neutron star, in a parallel universe where gravity is much stronger, and within eusocial hive societies.
The Xeelee Sequence explores numerous ideas from theoretical physics and futurology, including artificial wormholes, time travel, exotic-matter physics, naked singularities, closed timelike curves, multiple universes, advanced computing and artificial intelligence, faster-than-light travel, spacetime engineering, quantum wave function entities, and the higher levels of the Kardashev scale.
Thematically, the series addresses existential and philosophical issues such as the struggle for survival in an unknowable universe, the impact of war and militarism on society, and the consequences of an unpredictable technological future for humanity.
Plot summary
The overarching plot of the Xeelee Sequence involves an intergalactic war between humanity and the Xeelee, as well as a cosmic conflict between the Xeelee and the Photino Birds. Both are alien species that originated in the early universe. The technologically advanced Xeelee inhabit supermassive black holes, manipulating their event horizons to create habitats, construction materials, tools, and computing devices. The Photino Birds are a species based on dark matter that live in the gravity wells of stars. Because dark matter interacts only weakly with normal matter, they are likely unaware of baryonic life. To avoid losing their habitats to supernovae and stellar evolution, the Photino Birds interfere with nuclear fusion in stellar cores, prematurely aging stars into stable white dwarfs. These dwarfs provide long-lasting refuges for the Birds, but at the expense of other forms of life on surrounding planets. Their activities also halt the formation of new black holes by preventing Type II supernovae, thereby threatening the Xeelee and their cosmic projects.After enduring several brutal occupations by alien civilizations, humanity expands into the galaxy with a xenophobic and militaristic outlook, seeking to eradicate other species. Humans eventually become the second-most advanced and widespread civilization in the Milky Way, after the Xeelee. Unaware of the war between the Photino Birds and the Xeelee, and its cosmic stakes, humanity wrongly concludes that the Xeelee are a sinister threat to their hegemony. Through a long war of attrition, humans contain the Xeelee to the galactic core. Both sides use time travel and closed timelike curves as war tactics, producing a stalemate that lasts thousands of years. Eventually, humanity develops defensive, movable pocket universes to safeguard information and an exotic weapon capable of destabilizing the core’s supermassive black hole. After the first successful strike, the Xeelee abruptly withdraw from the galaxy, ceding the Milky Way to human control.
Over the next 100,000 years, humanity continues to advance technologically, becoming a Type III civilization. They spread across the Local Group of galaxies and wage further wars against the Xeelee. However, even at this peak, humans remain a minor distraction, unable to meaningfully challenge Xeelee dominance across the wider universe.
Although the Xeelee master space and time and can even influence their own evolution, they ultimately fail to stop the Photino Birds. Instead, they construct a colossal ring-like structure made of cosmic strings. This construction, known as Bolder’s Ring, enables escape to other universes. Despite their aloofness and superiority, the Xeelee show compassion toward younger species. For example, they create a tailored universe for the nearly extinct Silver Ghosts, and they allow humans to use the Ring despite their long hostility.
Novels
''Xeelee Sequence'' (1991–2018)
Not all printings included volume number.| Title | Publisher | Date | ISBN | Notes | |
| 1 | Raft | Grafton | July 1991 | ||
| 2 | Timelike Infinity | HarperCollins | December 1992 | ||
| 3 | Flux | HarperCollins | December 1993 | ||
| 4 | Ring | HarperCollins | July 1994 | ||
| 5 | Vacuum Diagrams | HarperCollins | April 1997 | Short story collection; Philip K. Dick Award winner, 1999 | |
| 6 | Xeelee: Endurance | Gollancz | 17 September 2015 | Short story collection | |
| 7 | Xeelee: Vengeance | Gollancz | 15 June 2017 | ||
| 8 | Xeelee: Redemption | Gollancz | 23 August 2018 |
''Destiny's Children'' (2003–2006)
Series of thematically-linked novels set within the main Xeelee Sequence. Published by Gollancz.| Title | Date | ISBN | Notes | |
| 1 | Coalescent | 9 October 2003 | Arthur C. Clarke Award nominee, 2004 | |
| 2 | Exultant | 23 September 2004 | ||
| 3 | Transcendent | 27 October 2005 | John W. Campbell Memorial Award nominee, 2006 | |
| 4 | Resplendent | 21 September 2006 | Short story collection |
Short fiction
Short fiction set within the Xeelee Sequence. Below is an incomplete list:| Title | Original publication | Issue date | Baxter collection |
| "The Xeelee Flower" | Interzone | Spring 1987 | Vacuum Diagrams |
| "More Than Time or Distance" | Opus Quarterly | Winter 1988 | Vacuum Diagrams |
| "The Eighth Room" | Dream Science Fiction | Summer 1989 | Vacuum Diagrams |
| "The Switch" | The Edge | March/April 1990 | Vacuum Diagrams |
| "Vacuum Diagrams" | Interzone | May 1990 | Vacuum Diagrams |
| "The Tyranny of Heaven" | Dream Science Fiction | July 1990 | Vacuum Diagrams |
| The Baryonic Lords, Part One | Interzone | June 1991 | Vacuum Diagrams |
| The Baryonic Lords, Part Two | Interzone | July 1991 | Vacuum Diagrams |
| "The Gödel Sunflowers" | Interzone | January 1992 | Vacuum Diagrams |
| "Planck Zero" | Isaac Asimov's Science Fiction | January 1992 | Vacuum Diagrams |
| "The Sun Person" | Interzone | March 1993 | Vacuum Diagrams |
| "Chiron" | Novacon 23 | November 1993 | Vacuum Diagrams |
| "Lieserl" | Interzone | December 1993 | Vacuum Diagrams |
| "The Logic Pool" | Asimov's Science Fiction | June 1994 | Vacuum Diagrams |
| "Cilia-of-Gold" | Asimov's Science Fiction | August 1994 | Vacuum Diagrams |
| "Hero" | Asimov's Science Fiction | January 1995 | Vacuum Diagrams |
| "Gossamer" | Science Fiction Age | November 1995 | Vacuum Diagrams |
| "Soliton Star" | Asimov's Science Fiction | May 1997 | Vacuum Diagrams |
| "Cadre Siblings" | Interzone | March 2000 | Resplendent |
| "Silver Ghost" | Asimov's Science Fiction | September 2000 | Resplendent |
| "On the Orion Line" | Asimov's Science Fiction | October/November 2000 | Resplendent |
| "The Ghost Pit" | Asimov's Science Fiction | July 2001 | Resplendent |
| "The Cold Sink" | Asimov's Science Fiction | August 2001 | Resplendent |
| "The Dreaming Mound" | Interzone | May 2002 | Resplendent |
| "Breeding Ground" | Asimov's Science Fiction | February 2003 | Resplendent |
| "The Great Game" | Asimov's Science Fiction | March 2003 | Resplendent |
| "The Chop Line" | Asimov's Science Fiction | December 2003 | Resplendent |
| "Ghost Wars" | Asimov's Science Fiction | January 2005 | Resplendent |
Anthologies
Previously anthologized short fiction.| Title | Original collection | Editor | Publisher | Date | ISBN | Baxter collection |
| "Blue Shift" | Writers of the Future, Vol. V | Algis Budrys | Bridge Publications | May 1989 | Vacuum Diagrams | |
| "The Quagma Datum" | Interzone: The 4th Anthology | John Clute, et al. | Simon & Schuster | August 1989 | Vacuum Diagrams | |
| "In the Un-Black" | Redshift Extreme | Al Sarrantonio | Roc Books | December 2001 | Resplendent | |
| "Conurbation 2473" | Live Without a Net | Lou Anders | Roc Books | July 2003 | Resplendent | |
| "All in a Blaze" | Stars | Janis Ian and Mike Resnick | DAW Books | 5 August 2003 | Resplendent | |
| Between Worlds | Between Worlds | Robert Silverberg | SFBC | August 2004 | Resplendent | |
| "Lakes of Light" | Constellations | Peter Crowther | DAW Books | 4 January 2005 | Resplendent | |
| "Remembrance" | The New Space Opera | Gardner Dozois and Jonathan Strahan | HarperCollins | 12 June 2007 | Endurance | |
| The Seer and the Silverman | Galactic Empires | Gardner Dozois | SFBC | February 2008 | Endurance | |
| The Return to Titan | Godlike Machines | Jonathan Strahan | SFBC | November 2010 | Endurance | |
| "The Venus Generations" | Bridging Infinity | Jonathan Strahan | Games Workshop | 20 October 2016 | — |
Limited edition novellas
Limited editions distributed by UK-based PS Publishing. Mayflower II won the 2004 BSFA Award for Best Short Fiction.| Title | Date | ISBN | Baxter collection |
| Realty Dust | 31 March 2000 | Resplendent | |
| Riding the Rock | 30 November 2002 | Resplendent | |
| Mayflower II | 1 April 2004 | Resplendent | |
| Starfall | 12 January 2009 | Endurance | |
| Gravity Dreams | 15 April 2011 | Endurance |
Old Earth (2004–2009)
Short stories published as "A Tale of Old Earth". Stories are collected in Xeelee: Endurance.| Title | Original publication | Issue date |
| "PeriAndry's Quest" | Analog Science Fiction and Fact | June 2004 |
| "Climbing the Blue" | Analog Science Fiction and Fact | July/August 2005 |
| "The Time Pit" | Analog Science Fiction and Fact | October 2005 |
| "The Lowland Expedition" | Analog Science Fiction and Fact | April 2006 |
| "Formidable Caress" | Analog Science Fiction and Fact | December 2009 |
Chronology and reading order
The novels in chronological order are given below. Some of the novels contain elements occurring at different points in the timeline. The story anthologies each contain stories taking place across the entire chronology.| Title | Publication | Chronology | Notes |
| Coalescent | 2003 | 476–2005 | Part 1 of Destiny's Children |
| Transcendent | 2005 | 2047 | Part 3 of Destiny's Children ; the world of Michael Poole Bazalget |
| ' | 2017 | 3646–3665 | Set in an alternate timeline |
| ' | 1992 | 3717 | Majority of the plot concerns events that begin here, with later major events occurring in 3829 and the 5000s. The final chapter takes place mainly in. |
| Ring | 1994 | 3951 | Before Great Northern launches |
| 2018 | Set in the same alternate timeline as Xeelee: Vengeance | ||
| Exultant | 2004 | Part 2 of Destiny's Children | |
| Raft | 1991 | ||
| Flux | 1993 | ||
| Transcendent | 2005 | Part 3 of Destiny's Children; the world of Alia | |
| Ring | 1994 | After Great Northern returns |
In 2009, Baxter posted a detailed chronology of the Xeelee Sequence explaining the proper chronological reading order of all the novels, novellas, and short stories up to that year. The timeline was updated in September 2015.
When asked directly for a suggested reading order, the author wrote: "I hope that all the books and indeed the stories can be read stand-alone. I'm not a great fan of books that end with cliff-hangers. So you could go in anywhere. One way would be to start with Vacuum Diagrams, a collection that sets out the overall story of the universe. Then Timelike Infinity and Ring which tell the story of Michael Poole, then Raft and Flux which are really incidents against the wider background, and finally Destiny's Children."