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 military at some point — especially during the era when we had a compulsory draft. But how did serving in the military shape these writers' books? Here's a look at 15 of the authors who served in the armed forces, and how their work reflects that experience.