Games Workshop has been trying to own the term "Space Marine" — but would their Space Marines be able to pwn the Spartans from Halo? And Heinlein's Starship Troopers? What about the Colonial Marines from Aliens, or Doctor Who's deadly clergy? Which space army would defeat all the rest?

This weekend, we celebrate the awesome majesty of superpowered suits of armor, with Iron Man 3. But the "power armor" genre has a long and kick-ass history, spanning decades of battles and adventures. Here are the 10 most essential power-armor stories of all time!

Elon Musk is making all of our dreams of independent space flight come true, and he wants to put humans on Mars. He may even succeed. But what inspires him? Some classic science fiction books, apparently.

Back in December, when Games Workshop first got M.C.A. Hogarth's Spots the Space Marine novels pulled from Amazon.com, claiming to own the trademark for "space marine," this seemed like a misunderstanding. Or an overzealous legal department. After all, the term "space marine" goes back to the 1930s and has been used by…

So much of science fiction's core topics intersect with war, one way or the other. Rapid social change and technological innovation both get supercharged during wartime, and some of our greatest explorers are also warriors. So it's not surprising that many of science fiction's most well-known authors served in the…

People tend to divide Robert A. Heinlein's career into three different eras, with the "juveniles," the "slick" science fiction stories, and the bigger, more opnionated novels. But over in Locus Magazine, Gary Westfahl has a theory that's sure to be controversial: Heinlein's career actually divides into a slew of serious…

Even the greats get Writer's Block. But when you're Theodore Sturgeon, you can get some advice directly from Robert A. Heinlein.

This weekend belongs to time travel. We're finally seeing the long-awaited release of Looper, the Terminator-inspired gangster movie. And Steven Moffat is writing what I'm guessing will be another timey-wimey episode of Doctor Who. So now's a great moment to think about time travel, and what makes it especially cool.

War changes everything. War is an apocalypse and a technological revolution and a life-changing adventure, all rolled into one. So it's not surprising that many of science fiction's most indelible stories are about warfare.

Part of the joy of science fiction is seeing all the awesome toys, and imagining how they could exist in the real world. And so many of science fiction's coolest gadgets have come true, including Star Trek's PADDs and communicators.