Tony's Review of Fantastic Voyage

Fantastic Voyage is one of those rare science fiction novels that began as a film concept and then became a book. Isaac Asimov took the screenplay and gave it his signature clarity and scientific grounding, turning what might have been just a visual spectacle into a thoughtful adventure story. While the story itself was from the minds of Otto Klement and Jerome Bixby.

The premise is strikingly original. A team of scientists and doctors are miniaturized, along with a submarine, and injected into the bloodstream of a man whose life depends on delicate surgery. They must travel through the body itself, navigating the arteries, heart, lungs, and brain, all while racing against the time limit imposed by the temporary nature of miniaturization.

Asimov brings a sense of believability to what is essentially impossible science. He was reluctant to even start work but was eventually persuaded the idea itself presented a story. He describes the human body as a landscape, a strange new world that is both familiar and alien. Blood cells become like drifting life forms, and the heart is a cavern of power. This transformation of biology into setting is what makes the novel so compelling.

There are, however, differences between the book and the movie. The 1966 film is more focused on spectacle and the visual wonder of traveling inside the body. Asimov, by contrast, deepens the logic, explaining the limits of miniaturization and tightening the science behind the journey. The film ends in a slightly more dramatic fashion, with the crew narrowly escaping the body. The novel’s ending is more deliberate, and Asimov even corrected some of the scientific oversights from the script as he adapted it.

It is also worth mentioning that years later, in 1987, Asimov revisited the idea in Fantastic Voyage II: Destination Brain. This was not a sequel to the first book, but rather a complete reimagining of the miniaturization concept. Unlike the original, which was tied closely to the movie script, Destination Brain is entirely Asimov’s own creation, with more depth in both the characters and the scientific speculation. In many ways, it shows how much the author had grown and how he wanted to fully own the idea without the limits of adapting someone else’s story.

What makes Fantastic Voyage stand out is the blend of tension and imagination. It is part medical thriller, part exploration story. The danger is not from aliens or cosmic horrors, but from the human body itself. The immune system, the flow of blood, and the vast machinery of biology become both setting and antagonist.

The novel is not as philosophically deep as I, Robot or the Foundation series, but it does what it sets out to do: it makes the impossible feel possible. The idea of shrinking down to explore the inner world of the body has since become a cultural touchstone, inspiring countless parodies, homages, and even cartoons.

In the end, Fantastic Voyage is a unique work that sits at the crossroads of science fiction literature and film. Paired with Destination Brain, it shows both Asimov’s craftsmanship and his ability to take even the wildest premise and give it scientific and narrative weight.