Scientists know things. Important things. And for years, that’s terrified the FBI.

The terror isn’t entirely unjustified. Some researchers have betrayed their country. But much of the bureau’s surveillance of the country’s brightest minds has been baseless, at best.

That’s the message of a forthcoming book, “Scientists Under Surveillance,’’ which digs into the FBI files of some of the most famous scientific figures of the 20th Century, from Albert Einstein, to Carl Sagan, to Timothy Leary.

One local target: Isaac Asimov. Best known as a science fiction writer, he was also a biochemistry professor, starting in 1949, at the Boston University School of Medicine.

The decision to initiate Asimov’s file began with a tip to then-FBI Director J. Edgar Hoover. A redacted source had wrangled with Asimov over the scientist’s (accurate) claim in his 1956 book, “Inside the Atom,’’ that the first nuclear power plant built in the Soviet Union, not the US. Researching a rejoinder, the source learned that Asimov had been born in Russia. From these revelations, suspicion blossomed.

The FBI file, opened in 1960, consists of a dictionary definition of biochemistry and some speculation that Asimov might be ROBPROF — the codename for a known Soviet informant in America with a background in microbiology; never mind that Asimov, the would-be ROBPROF, had actually stopped teaching nearly a decade earlier.

The investigation into Asimov never revealed any grand plot against the United States, fictional or otherwise. Still, the FBI kept Asimov’s file open until his death in 1992.

Below, JPat Brown, one of the editors of “Science Under Surveillance,’’ walks us through a page from Asimov’s FBI file.

Why did the American government fret so much about science fiction?

The short answer is that imagining a different world is a very dangerous idea.

Science fiction projects a reality far beyond the status quo. That can be extremely threatening when there’s an active interest in making sure people don’t think too far outside the box. Images of a post-nuclear or post-World War III world with massive casualties, for example, were seen as a deliberate psychological attack on our ability to fight these kinds of wars [in the future].

I think there was this idea that you can’t stop people entirely from doing this, but you had to keep a close eye on it.

The FBI document goes to great lengths to position Asimov as an expert in microbiology and biochemistry. Why was his knowledge of science viewed as a threat?

That’s one major theme in our book. These days, we consider science to be objective, politically neutral, and apolitical. Purely scientific ideas are nice in theory, but as soon as they’re put into actual practice and actual political friction is in play, then they immediately take on a whole different life.

Did the FBI ever find ROBPROF?

It may have been multiple people. The fascinating problem with trying to dig into this kind of history is that you’re working off of incomplete lists from 50 years ago that are heavily redacted and based off a lot of guesswork. The actual identity these people is still a mystery.

The file says it’s putting the ROBPROF case in “pending inactive status.’’ What does that mean?

Just because someone is being investigated by the FBI doesn’t necessarily mean the agents are trying to link that person to a specific crime. The thing about a lot of the FBI files we’ve studied is that it’s clear that the investigators were trying to create an Internet before there was an Internet — a place where, if you wanted to keep track of these kinds of people, you could collect as much information as possible on them and compile it in a way that it could be easily accessed and cross-referenced.

These files were kept on hand in case another informant suggested something that might have further implicated Asimov as ROBPROF, or as a more ardent communist than was led to believe. Had that happened, the FBI would have reopened the investigation to prove this connection.

From this document, it’s clear that the agents were certainly open to the idea that Asimov might come up again — that’s why they did not definitively close him as a possible lead — but uncertainty shifted the effort to a more passive information-gathering process.

Why was Asimov’s file updated seven years after it was opened?

As you can see, the file shows that the FBI conducted a comprehensive biographical sketch of Asimov at multiple points in his life — addresses, criminal records, et cetera. Think of it like a Facebook profile; the FBI was the original collector of that kind of information. You can draw a direct line from Facebook to the FBI.

You know, we all have files open on us until we’re dead. Until there’s reason to stop collecting information, you keep collecting information.

Aimee Ortiz can be reached at aimee.ortiz@globe.com. Follow her on twitter @aimee_ortiz.