GWEN IFILL: In New York City last night, what has become an annual tribute to the victims of the 9/11 terrorist attacks lit up the sky once again.

The display, which marks where the Twin Towers once stood, remembers those lost that day.

A new book about one of the victims, a passenger on the first hijacked jet, talks about life, as well as loss.

Ray Suarez has our conversation.

RAY SUAREZ: Danny Lewin was one of 92 people aboard American Airlines Flight 11 on September 11, 2001, originally heading to Los Angeles.

But terrorists took over the plane and flew it into the World Trade Center North Tower.

Lewin's role has been largely unknown until now.

But it is believed that he tried stopping the hijacking before the plane flew into the tower, and was killed in the struggle.

Lewin was a 31-year-old Internet entrepreneur.

He had a major role in transforming the way the Web worked and working on algorithms that speeded up the delivery of content considerably.

His story is the subject of a new book, "No Better Time: The Brief, Remarkable Life of Danny Lewin, the Genius Who Transformed the Internet."

The author is Molly Knight Raskin, a journalist who has also worked previously for the NewsHour.

Molly, good to have you with us.

MOLLY KNIGHT RASKIN, "No Better Time": The Brief, Remarkable Life of Danny Lewin, the Genius Who Transformed the Internet": Good to be here.

RAY SUAREZ: Well, this is your first book.

What got you interested in the story of Danny Lewin?

MOLLY KNIGHT RASKIN: Well, I first heard about Danny on the 10th anniversary of 9/11,

which surprised me, because I thought I had heard so many stories until then, and didn't really expect to hear a story that I would want to go out and tell.

And a friend of a friend came to me and said, there's a story of this victim of 9/11.

And his company, which is based in Cambridge, wants to produce a documentary about him as a tribute.

And this was a private thing.

But the more I learned about his life and began to research and interview people, the more I just felt that it was a story that needed to be told.

RAY SUAREZ: You know, that idea, the man who saved the Internet, that's a pretty big title to hang around anyone's neck or put on their resume.

How did he do it? What was the problem?

Take us back to the late '90s and the growing pains of the World Wide Web.

MOLLY KNIGHT RASKIN: Well, I think everybody, if you used the Internet back then, or You tried to, in the mid-'90s, the biggest impediment to the growth of the Internet was really this problem of congestion.

The Internet is a distributed system, and it still is today, and so instead of having one tunnel through which information can be processed and content can be sent,

there's this whole sort of tangled web of roots through which all this content passes every day.

And, basically, Danny wrote a set of algorithms for his thesis at MIT, and he came up with this idea that, by using math, combined with theoretical computer science, he could have some practical application to the Internet,

and he could end what at the time was being called the worldwide wait.

If you remember, you would dial into a Web site, and, you know, these days, it would probably seem like an eternity.

You would wait and wait and you would hear the beeping and chirping, and then most of the time, you would get the message, please wait, the server is busy.

And so, in that environment, it was almost impossible to grow an e-business, where people needed to click and they needed to get products or information fast.

So, Danny wrote this set of algorithms. And, basically, what he did was use them to program software, which he patented with his professor at MIT Tom Leighton, and create this distributed system, a layer on top of the Internet that functioned in a very different way, that used his math to make intelligent software that was like a FedEx for the Internet.

It knew the fastest route and it knew how to get around the traffic jams.

RAY SUAREZ: It was a sensation from its first days of taking on some big customers.

But when the dot-com bubble burst, the company started to sail through some rough waters.

September 11 casts a long shadow across this book, and I think one of the most beautiful, karmic convergences of the whole thing is when the story of September 11 itself backs one of the first mega-news stories of the Internet age, and it's the day that kills Danny Lewin at the same time.

MOLLY KNIGHT RASKIN: Yes, it's really the tragic irony of the story.

I mean, Danny spent so many years going out there and trying to sell this technology.

And in the early days, it wasn't easy. And he basically said, there will be a day on which the Internet will get a crush of requests.

It will be a crush unlike anything you have ever seen.

And everything he predicted proved true on that day 12 years ago.

And he, sadly, perished that day, and was unable to see his company not only survive the crash, but also Akamai Technologies, the underpinnings of which were his algorithms, were responsible for keeping all of these websites live on September 11 that people used who were in desperate search of information about lives that were lost.

It was -- it was the Web equivalent of the 100-year flood.

And websites like CNN.com were struggling and, in fact, crashed that morning, and the first call a lot of them made was to Akamai.

RAY SUAREZ: In a tribute to Danny Lewin, one of his best friends called him the first casualty of the first war of the 21st century.

What do we know about the way he died?

MOLLY KNIGHT RASKIN: Well, we don't know exactly what happened on Flight 11, and we never will.

It happened very fast.

It happened before really anybody knew anything about that terrible day.

But what we do know from the facts gathered by the 9/11 Commission is that the passenger seated in 9-B in business class, which was Danny's seat, according to the flight manifest, was stabbed and killed in some kind of a struggle on that flight.

And we also know that Danny was a trained warrior.

He had trained in one of the most elite counterterrorism units of the Israeli army.

So his friends and family say, the moment they heard about the crash and knew that there had been a struggle in his seat, that he had stood up and tried to fight back. And, at that time, nobody had perished yet from the attacks.

RAY SUAREZ: The book is "No Better Time."

Molly Knight Raskin, thanks for joining us.

MOLLY KNIGHT RASKIN: Thanks for having me.