Star Trek: Cast No Shadowby James SwallowPocket Books, 2011Industry veteran James Swallow's latest Star Trek novel, Cast No Shadow is, like all Star Trek fiction, almost exclusively intended for fans of the show and the movies. This atmospheric barrier is obvious immediately: who but such a fan would even pick up, much less buy, a paperback with such a forebodingly uninviting cover? To Star Trek newcomers or, God forbid, just your average science fiction fans who might conceivably encounter this book on the New Releases shelf of the bookstore's Sci-Fi section, there is only dismay as far as the eye can see: bland, mechanical design, badly Photoshopped background, and these two enormous heads, a grim older man almost completely blocking a grim middle-aged woman.The whole concept of a book cover's general appeal isn't so much ignored as willfully cast aside, and the same is true for the book itself. The point is, Star Trek fans will at once recognize not only an old-age version of the iconic Mr. Spock but also, peeping out from behind him, Lieutenant Valeris. Valeris was the traitorous villain of University of Iowa grad Nicholas Meyer's 1991 box-office hit "Star Trek VI: The Undiscovered Country," in which she uses her position as Mr. Spock's star pupil to lie and kill her way to sabotaging peace-talks between the Federation and the Klingon Empire. At the climax of that movie, our beloved Spock uses telepathy to mind-rape the unwilling Valeris in order to learn the names of her co-conspirators, and that's the last we see of her.Fans have of course speculated endlessly on the background of Valeris, what connection ('if any' need hardly be added - these are Star Trek fans we're talking about, after all) she has with Lieutenant Saavik, Mr. Spock's previous star pupil (he doesn't mind-rape her, but they do have good old-fashioned sex - at times it's difficult knowing why it's Kirk who has the reputation for randiness), and most of all, what happened to Valeris after the events of "The Undiscovered Country."Cast No Shadow exists to satisfy all those curiosities - it's a niche-franchise addendum to the events of a 20-year-old science fiction movie. That having been said, it's quite good.Naturally, it feels a bit defeated to say so. I mean, who cares if it's quite good, considering that it's not only going to reach about a thousand readers but was self-consciously designed to reach no more than that? I presume James Swallow got a contract to write this thing, and I'm guessing Paramount checks don't bounce. That's good. And the book will further solidify Swallow's good standing among Star Trek fans (he wrote a very good episode of "Star Trek: Voyager" and then, years later, he wrote a borderline-great episode of the same show). Since the only things that are "real" in Star Trek continuity are the things that happen on the movie screen, nothing in Cast No Shadow will ever be "definitive," but then, it's extremely unlikely that anybody with a film crew is ever going to re-visit the story of Valeris, so this book is as close to canon as any book can be.Swallow has given the product an ambitious three-strand helix of a shape, and he executes it flawlessly. That execution is far more tricky than it looks, since the book's narrative bounces between three different time-periods with almost video-game hyperactivity. We follow the young Valeris as she and her family endure horrors at the hands of the Klingons (hence her life-long hatred, unexplained in the film), watch her meet the Star Fleet hard-liners who want no peace with their long-time enemies. We follow Valeris at the time of "Undiscovered Country," hiding her true politics from Captains Kirk and Spock. And we follow Star Fleet prisoner Valeris as she's sent on a mission to infiltrate (or is it to rejoin?) a vicious terrorist group still hell-bent on shattering the fragile peace between the Federation and the Kingons.There are cameo appearances by many old familiar faces (at a commencement address, for example, Captain Kirk tells his audience that the nature of their Star Fleet duty is "challenge" - a nicely characteristic note), and Swallow gives us two outstanding new characters, sexy no-nonsense Starfleet Lieutenant Elias Vaughn and amusingly deadpan Klingon major Kaj. Swallow has been writing professional fiction for years, so no balls are dropped in the course of this book - the dialogue is speakable, the action sequences (a notorious weak spot in science fiction in general and Star Trek fiction in particular) all work, and there are surprises a-plenty.Star Trek fans will find quite a bit to entertain them here (I am unabashedly one such fan, and I couldn't put the book down - Swallow is considerably more talented than the usual authors rung in to write these things), and as for reaching out to non-Star Trek fans, well ... so far, that's where no Star Trek novel has gone before.