Writing popular fiction

researched
in any library with a good selection of historical reference texts.
    Only one main brand of error is endemic to the time travel tale: the
time paradox
. The term is best explained through examples, which are limitless. For instance:
    If you traveled back to last Thursday morning in a time machine and met yourself back then and told yourself to invest in a certain company because their stock would soar during the next week, what would happen if the Early You did as the Later You wished? When the Later You returned to the present, would he find himself rich? Or perhaps, while the Early You was running to the stock broker, he was stricken by an automobile and suffered two broken legs. When the Later You returned to the present, would he find himself with two broken legs? Perhaps you would end up hospitalized, never having been able to make the trip in the first place because your legs were broken a week ago. Yet, if you had never taken the time trip, you wouldn't have sent your Early Self into the path of the car and would not have broken legs. Yet, if you
did
make the trip, and
had
the broken legs, you
couldn't
have made the trip
because of
the broken legs and…
    Do you see what a time paradox is?
    Here's another:
    Suppose your hero went back in time and killed the villain ten years in the past. The villain would cease to exist at that point. Any children he had fostered would cease to exist if they had not been fathered before that day ten years ago. Did you really mean to kill his innocent children as well as him?
    Or suppose you traveled back in time and married your great-grandmother. Would you be your own great-grandfather?
    If you returned again and again to the same general period in time, wouldn't there be a whole crowd of you walking around?
    If you go into the future and see something unpleasant in your own life, and you come back to the present to make sure that the future thing never happens—can you really hope to change the future? If you've already seen yourself dying in a wrecked automobile, can you return to the present and avoid that accident? If you've seen it, isn't it already predestined?
    To better understand the complications you must deal with in the time travel story, read
Up the Line
, a modern classic of the form by Robert Silverberg, published by Ballantine Books. Silverberg purposefully generates every conceivable time paradox and carries them all to their wildly absurd and fascinating conclusion.

NEW DISCOVERY STORY
    If you don't feel up to the confusion of time travel, perhaps the fourth type of science fiction plot will intrigue you: the
new discovery story
. First, you conjecture a new discovery—it may be a device, process, or simply a theory—which would revolutionize modern life. You then concern yourself with detailing the effects that discovery has on society and, more immediately, upon your small cast of characters.
    Harry Harrison's
The Daleth Effect
deals with the discovery of a simple, relatively inexpensive stardrive which will permit space travel at a ridiculously low cost. Suddenly, the stars are ours—not in thirty or fifty or a hundred years, but
now
. The powerful social force of this process or device (Harrison never makes that entirely clear) spreads antagonism among world governments, because if any one country owned the Daleth Effect, it would soon so dominate as to make other nations powerless.
    Wilson Tucker's
Wild Talent
deals with the emergence of ESP abilities in the first of a new breed of human beings and details the fear and doubt such a discovery would cause in today's society.
    It is not essential, in the new discovery story, to adequately explain, through present-day science or pseudo-scientific double-talk, how the discovery
works
. It is always preferable, of course, to ground the device in a bedrock of acceptable scientific theory. But this type of science fiction story is far more concerned with the "how" and the "what" than with the technical-theoretical "why." And, since it usually takes place in the present or the very near future, it is the story type which requires the least amount of extrapolation and research. Indeed, many new discovery science fiction novels are set in such a near future that they are not labeled as science fiction, but as suspense: Michael Crichton's best-selling
The Andromeda Strain
, and
The Tashkent Crisis
by William Craig.

SCIENTIFIC PROBLEM STORY
    Fifth, we have the
scientific problem story
.. This form