Time travel has played a major part in the Star Trek universe. I can remember details of at least two Star Trek episodes involving time travel. Considering the matter, I have recalled at least six episodes of The Next Generation in which time travel or temporal events were a major part of the plot. Deep Space Nine has created at least three stories, one of them the excellent two-parter on the Bell Riots, another the return to the tribbles episode of the original show, and the third the very humorous Roswell incident--and it also includes a couple jumps sideways in time to an alternate universe earlier visited by Captain Kirk. The otherwise excellent Voyager upset me by massacring time in three disastrous episodes in one season, textbook examples of shoddy temporal thinking. There was even at least one episode of the Star Trek cartoon series in which time was altered and had to be repaired. Were we to undertake an exhaustive study of time travel in Star Trek, we would require far more space than we have for the web site, and far more time than I would be able to contribute to typing!
But it has not been our objective to examine time travel in all media. I have ignored some wonderful television shows on the subject, from Time Tunnel to Quantum Leap to Time Trax, because they are not movies (not to mention that I don't have all of the episodes of any of these available for review). This web site has focused on films, and of the eight Star Trek movies released to date, there are three in which time travel has played a part; therefore, we will examine those three movies. Even here, we will find the thinking uneven--they are not all good, but they are not all bad, either. So let me invite you to consider the three Star Trek movies which revolve around time travel: