Leonard Kleinrock, pioneer of the mathematical theory of packet networks, at the University of California, Los Angeles.

On Oct. 29, 1969, in a windowless room at U.C.L.A. a message was sent to the Stanford Research Center from a very large machine.

It was supposed to be “login,” but only the first two letters transmitted. So, the message was, simply, “lo.”

“We had no idea — we had nothing ready, because all we wanted to do was to log in,” Leonard Kleinrock, one of the men who sent that message, told me last week. “But we couldn’t have asked for a more succinct, more prophetic, more powerful message than, ‘lo.’”

As in, “Lo and behold.”

The message was the first ever sent between two computers. It was transmitted on a network called Arpanet. And from it, the internet was eventually grown. Of course, that’s a vast oversimplification of the momentous technological feat that this was.


A record of the first message ever sent over the Arpanet shown on an exact copy of the IMP log.
Credit…Rozette Rago for The New York Times

[From The Times’s archives, here’s an interview with Mr. Kleinrock in 1999.]

On the day that I met Mr. Kleinrock in that same windowless room — which has been largely preserved as a kind of mini-museum documenting the birth of the internet — lawmakers in Washington were grilling Mark Zuckerberg about Facebook allowing hate speech and disinformation to flourish on its platform, which reaches billions of people. Mr. Zuckerberg, Facebook’s chief executive, was there to defend his company’s project developing a kind of digital money.

Mr. Kleinrock, 85, said he first got interested in electrical engineering when, as a child in New York City, he made himself a crystal radio.

When U.C.L.A. offered him a job teaching engineering, he left his position as a researcher at the Massachusetts Institute of Technology to move out west.

Moving around the room and gesturing to decades-old equipment or diagrams hung on the walls, Mr. Kleinrock was clearly practiced at explaining packet switching and queuing theory. After more than five decades, he’s a comfortable, genial lecturer, even in one-on-one conversation.


The Interface Message Processor photographed at the University of California, Los Angeles.
Credit…Rozette Rago for The New York Times

But the story of how that message ended up being sent has been told by people who understand computers better than I do. What I wanted to know was how he now sees the world he helped create.

What, if anything, would he change about the way the internet has evolved? Did he have any regrets?

Mr. Kleinrock said his feelings were complicated.

He noted that in a news release issued by U.C.L.A. announcing Arpanet’s deployment, he is quoted as accurately predicting that “we will probably see the spread of ‘computer utilities,’ which, like present electric and telephone utilities, will service individual homes and offices.”

He said he thinks the network will become even more invisible than it is now, which seems likely.

But what he and his researcher colleagues missed, Mr. Kleinrock said, was the social side of the network. And he missed the ways in which that capability would, he wrote in an email later, “impact every aspect of our society.”

A few years ago, as hacking and spam and other undesirable uses of the internet proliferated, he said he often told people that the internet was in its disobedient teenage years, that it would grow out of its immature period.

That hasn’t happened.

“What’s happened is, it’s now more mature and what’s going on?” he said. “We have nation states putting boundaries around their national networks. We have organized crime, pilfering, money laundering and we have extremists shouting things on a network.”

And if everyone’s talking at an equal level, he said, it’s natural that extreme ideas would command the most audience.

Mr. Kleinrock said he blames two things. One, he said he and the internet’s early builders could have headed off if they’d anticipated the need for it: Strong user authentication, as well as strong file verification.

That wasn’t something researchers built in because at the time, he said, they were trying to encourage wider adoption of the network so they could continue their research — not build barriers.

The second, in retrospect, may have been more inevitable: the commercialization of the internet.


“Lo” is the first word transmitted on the internet.
Credit…Rozette Rago for The New York Times

He said that in 1994, the first piece of spam reached the network: A pair of lawyers sent a message offering their services in winning a green card lottery.

“They were advertising their services on our research network — how dare they?” Mr. Kleinrock recalled. “So we sent the email back to them and said, ‘Stop, shame on you.’”

But it was too late. Mr. Kleinrock likened it to a kind of fall from grace.

[From 2005: An early look at a research project to re-engineer the internet.]

“We didn’t see the dark side emerging because of our culture, which was a bunch of good people working together,” he said. “We didn’t imagine we would reach a point where there would be a profit motive — we didn’t take out any patents, we didn’t try to own the I.P.

“This was an engineering challenge.”

Still, he said, not everything is bad.

He still marvels at the fact that, at one point, his 99-year-old grandmother and his granddaughter could be on the internet at the same time. And they’d be able to use it to talk to each other.

And he said that, at least in terms of privacy and security, it’s possible to make the internet better.

“The citizenry has to get involved, the government has a role,” Mr. Kleinrock said. “And the scientists have a role.”