n alien cop known only as the Hunter speeds through space, chasing a nameless criminal of his own species. Both Hunter and Fugitive are ameboid intelligences, biologically closer to viruses than human beings. In their natural environment they live in close symbiosis with other forms of life, living beneath the skin and providing both companionship and certain custodial services in exchange for the shelter of warm bodies.
The Fugitive, who has shown a total lack of regard for the safety of his hosts, must be found and brought to justice ... but the chase suffers a serious setback when both cop and bad guy crash into the ocean on Earth. Making his way to a nearby tropical island, the Hunter enters the body of a human boy named Bob, whose family lives and works there at an installation producing oil by biological means. But by the time the Hunter adjusts to his host, and figures out a way to make contact, Bob is on a plane, en route to a private school overseas.
Convinced that the fugitive also made his way to that sparsely populated little island, and determined to find him before he disappears into the greater human population of Planet Earth, Bob and the Hunter must get back home—and find a way to deduce which human being, among Bob's many fellow island inhabitants, unknowingly carries a dangerous criminal from beyond the stars.
Not a whodunit, but a "who harbors it"
A cop from space comes chasing a criminal from space. They crash-land on Earth. Each has to possess the body of an Earthling to continue this game of extraterrestrial cat-and-mouse.
We know what would happen in the hands of other storytellers. There would be car chases, explosions, action scenes, moments of brutality on the part of the bad guy, and hair's-breadth escapes on the part of the good guy. It could very easily be a B-movie, and indeed, it was a B-movie: The Hidden, which took this basic science-fictional concept and turned it into a series of kinetic gunfights. The initial assumptions of that film are so close to Hal Clement's that some critics, Harlan Ellison for one, accused the filmmakers of plagiarizing him. But even if it did, it was only in those opening assumptions. Needle is no action movie. It's a gentle puzzle story about a protean alien detective and his human host, Bob, whose challenge lies not in out-shooting the bad guy, or even stopping him before he does something monstrous: it's in identifying him at all, when all he has to do to remain invisible inside his carrier is simply do nothing.
It's a fun read, with good prose, likable protagonists, a strong sense of its sunny island setting, and a mystery that plays fair—and that was in fact written in part to rebut famed editor John Campbell's dictum that science-fiction mysteries were impossible. The mechanics of the Hunter/Human symbiosis are fascinating, and consistent throughout. The Hunter never develops powers convenient to the plot that he didn't enjoy in earlier chapters, and his limitations do provide a large part of the story's challenge. Clement's writing is clear and thoughtful and frequently charming. The book deserves its reputation as a classic.
That said, there are a couple of elements that read oddly to modern readers. First, we're never shown why this alien criminal is so evil that he has to be destroyed. We're given some vague hints, but he never does anything all that bad onstage (except set booby traps to hurt Bob, and even those can be counted as acts of self-preservation). Maybe it's best that we don't see him killing somebody or planning something similarly evil, as we probably would in a current novel. (Most current novels would place the fugitive's evil center stage, with massive body counts, sometimes to the detriment of the story and sometimes not; Robert R. McCammon, for one, wrote a fun fat horror novel called Stringer which in retrospect reads a lot like Needle translated into Texas splatterpunk terms.) But though Clement is way more interested in setting up the puzzle, it might have been nice to get some detail, even in passing, that would have given the crisis urgency.
Then there's another problem: the fact that, once informed of his otherworldly passenger, Bob seems perfectly comfortable with the notion of an alien jellyfish cuddling up next to his vitals, seeing through his eyes and arguing with him. There's no suggestion that he might find this discomfiting, let alone as an invasion of his personal space. Bob's friend, the kindly doctor, who becomes a confidante, takes the news with similar equanimity. Maybe their ability to accept this unusual development without excessive misgivings helps move the story along, and keep it down to a little more than 200 pages; Needle would have been a different book entirely if they'd panicked or otherwise treated the Hunter like an infestation as unwanted as his prey. But it would have felt more real if Bob had suffered the shrieking heebie-jeebie skeevies, at least once.
