More and better than any other writer, David Drake does this for the wars of the future and the men and women who will fight them. Like every science fiction writer, he assumes that certain technological developments have taken place. He also assumes, as all who write science fiction are forced to, that certain others have not taken place. (He is, of course, fully capable of making a different set of assumptions and writing a good story around those.) Self-appointed experts may disagree with the assumptions of the Hammer's Slammers stories. They know exactly what war in the far future will be like. That there will be no war, or that wars will be fought entirely by robots while human beings sit around hoping not to die at the end. Or whatever. We should ask them and all such experts whether they have made their fortunes in the stock market. If there really were people capable of predicting what life—and death—will be like a thousand years from now, they would be capable of predicting what those things will be like just a few years from now, wouldn't they? Of predicting it and making shrewd investments. After all, there are men who can jump a one-foot ditch but cannot jump a three-foot ditch; but there are no men who can jump a three–foot ditch but cannot jump a one-foot ditch. Prediction is a rifle, less accurate as the range increases.

We can argue with any assumption found in any science fiction story. It will give us a good bull session, and perhaps even a bit of enlightenment. Still, we cannot rationally deny these assumptions. In science, it is the happy fate of human kind to know what is possible but not what is impossible. In 1946, anyone who said that all the wars to come in the Twentieth Century would be non-nuclear would have been laughed to scorn.

On what basis, then, can we judge a science fiction writer's assumptions? (Assuming that they seem relatively plausible.) Reading any story in this book will supply the answer. Good science fiction assumptions are those that lead to a good science fiction story.