Forget about story, or character development. When it comes to selecting your science fiction reading material, you want a story that spans millions of years, if not billions. Or why not trillions, while you're at it? A truly grand space saga needs a lot of elbow room across history to unveil its cosmic events. So which novel, or series of novels, spans the longest time period? We rank them below.

Note: I disqualified stories where the backstory goes back billions of years. If an entity turns up that's already billions of years old, big whoop. We have to follow the story across those millions or billions of years, or it's not worth anything. Sorry, Rama!

House of Suns by Alistair Reynolds. This forthcoming novel is a quasi-sequel to the novella Thousandth Night, which takes place in the year one million A.D. (and appears in the anthology One Million A.D., edited by Gardner Dozois.) The sequel takes place around 6.4 million A.D., meaning the whole loosely-connected story spans about five million years. A galactic civilization challenged by the impossibility of faster-than-light travel decides to move all the inhabited star systems closer together to allow for easier trading and contact. Meanwhile, a post-human family specializes in reclaiming ancient ringworlds.
Time span: five million years, sort of.


Evolution by Steven Baxter. This novel in stories follows human evolution, from tiny mammals 65 million years ago to our posthuman and non-biological descendants 500 million years from now, when Earth is uninhabitable.
Time span: 565 million years.

The First And Last Men by Olaf Stapledon. This 1930 novel describes 18 stages of human evolution, across two billion years, ending with humans living on Neptune and being destroyed by a supernova. Lots and lots of funny-shaped heads, until the humans move to Neptune and become dwarves due to the high gravity.
Time span: two billion years.


The Lensmen novels by E.E. "Doc" Smith. The saga begins over two billion years ago, when the Arisians first realize they need to defend our universe against the marauding Eddorians, and start their breeding program on Earth. This leads to the "Lensmen" two billion years later, and the formation of the Galactic Patrol. It takes hundreds of years for the most deserving of the Lensmen to be born, in the endgame of the Arisians' eugenics program.
Time span: Over two billion years.

Spin by Robert Charles Wilson. This Hugo-winning novel cheats a bit on the aeons front, because alien machines put an artificial membrane around the Earth that blocks out the stars and causes time to pass much more slowly on Earth. One Earth year equals 100 million years for the outside world, so that four billion years pass within a single human generation. It turns out the alien machines put the membrane there because Earth's unsustainable development threatened its destruction.
Time span: four billion years.

The Xeelee sequence by Stephen Baxter. It stars, more or less, in the year 3000 when humans "open up" the solar system with wormhole technology. One of our heroes, Michael Poole, is born in 3621. Humans get embroiled in a long-running war with the alien Xeelee, and human planets are conquered by the Squeem and later by the time-traveling Qax. The Xeelee war begins in earnest in the year 100,000. The Xeelee defeat humanity in the year 1 billion, and then the story jumps forward to the distant future, with humans in the generation ship Great Northern on a five million year voyage, while an artificial intelligence named Lieserl explores the center of a sun. Humans learn how to leave our universe just in time to escape its destruction. The book Vacuum Diagrams has a Xeelee sequence chronology.
Time span: at least 10 billion years, probably more like 100 billion.

Macrolife by George Zebrowski. The Bulero family creates the super-strong (but highly explosive) material Bulerite which allowed humans to conquer space starting in 2021. And then in the year 3000, humans start merging with each other, and with cybernetic consciousnesses, into a kind of Borg-esque collective, which treats individual humans as cells in a body. And then finally in the year one hundred billion, one member of the Bulero family is "re-individualized" from the Macrolife collective to help figure out how to survive the end of the universe. He discovers some Macrolife survivors from previous universes.
Time span: one hundred billion years. In your face, Robert Charles Wilson!

Star Maker by Olaf Stapledon. Perhaps realizing that he was never going to win this contest with a paltry two billion years, Stapledon went back to the drawing board and came up with this 1937 story about a disembodied consciousness who leaves Earth and roams time and space. The story includes the thoughts of sentient clouds in the early universe, and roams all the way up to the heat-death of the cosmos. At one point, the main character meets the "Star Maker," the dispassionate creator of the universe.
Time span: billions and billions of years.

OK, I'm sure I missed some vital and awesome time-spanning storylines. What did I miss?