But today, more than 10 million people have tuned into Dr. Pausch’s last lecture, a whimsical and poignant talk about Captain Kirk, zero gravity and achieving childhood dreams. The 70-minute talk, at www.cmu.edu/randyslecture, has been translated into seven languages, and this week Hyperion is publishing “The Last Lecture,” a book by Dr. Pausch and a collaborator, Jeff Zaslow, that tells the story behind the story of the lecture.

“The whole thing is very strange,” Dr. Pausch said over lunch at a diner near Norfolk, Va. “I just gave a talk. I gave talks my whole life.”

But of course, this wasn’t just any talk. “Let’s not ignore the obvious,” he said. “If I’d given that lecture but I weren’t dying, it wouldn’t have had the gravitas. Context is everything.”

Dr. Pausch, 47, is dying of pancreatic cancer, a disease that kills 95 percent of its victims, usually within months of diagnosis. Except for a pill bottle on the table in front of him, there were no outward signs of the deadly tumors growing inside him. Though he had just recently recovered from heart and kidney failure, he looked boyish, with a red knit shirt and a head of thick dark-brown hair.

Last fall, after doctors told him that he would probably have no more than six months of good health, Dr. Pausch stepped down from his academic duties and relocated to be closer to his family. But he decided to give one last lecture to a roomful of students and faculty members at Carnegie Mellon.

The lecture was not about cancer. Instead, he says, it was simply a father’s effort to digest a lifetime of advice for his children into one talk — a talk that Dr. Pausch knew he would not be around long enough to deliver in person. The children are Dylan, 6; Logan, 4; and Chloe, almost 2.

Although he could have set it up on a home video, he liked the idea that one day they would watch his last lecture and see their dad at work, in his element.

“I’m speaking only to them,” he said. “I didn’t set out to tell the world about how to live life.”

After Mr. Zaslow, a Carnegie Mellon alumnus who is a columnist for The Wall Street Journal, wrote about the talk, it quickly became an Internet sensation.

With the clarity of thought that perhaps only a person facing death can muster, Dr. Pausch, in his lecture and his book, outlines his recipe for a happy life and achieving dreams.

He talks of reaching his childhood goals of experiencing zero gravity, writing an article in the World Book Encyclopedia, winning giant stuffed animals at amusement parks and being a Disney “imagineer.” Much of his talk is about tenacity and how he managed to scale the “brick walls” that stood in the way of achieving some of his dreams. Other lessons are those that all parents hope to teach their children — show gratitude, tell the truth, no job is beneath you.

And he urges parents to let their children draw on the bedroom walls — where the young Randy Pausch painted a quadratic equation, a rocket, an elevator and, from one of his favorite stories, Pandora’s box. At the bottom of the box, he added the word “Hope” that a friend later preceded with “Bob.”

Dr. Pausch says he is trying to use his unexpected celebrity to draw attention to the lack of financing for pancreatic cancer research. Testifying before Congress on behalf of the Pancreatic Cancer Action Network (www.pancan.org), he showed a picture of his family. “This is my widow,” he said pointing to his wife, Jai. “That’s not a grammatical construction you get to use every day, but there aren’t many diseases where you know it will be fatal.”

Because Dr. Pausch has outlived his initial prognosis, a few bloggers have begun to speculate that he is not really dying. Doctors at the M. D. Anderson Cancer Center in Houston and the University of Pittsburgh have confirmed Dr. Pausch’s diagnosis and treatment.

“There’s nothing to be cynical about in how he’s choosing to approach these last months of his life,” said Robbee Kosak, vice president for university advancement at Carnegie Mellon. “He’s always been very passionate. He’s always very pragmatic. He knows exactly what his priorities are. People like Randy are so rare. We should all be really happy that so many of us have had a chance now to see that it’s possible to live your life with passion and energy and candor.”

Although Dr. Pausch let Diane Sawyer prepare a one-hour special for ABC-TV about his talk and cancer battle that will be broadcast on Wednesday evening, he has turned down movie offers and even declined an approach from a documentary filmmaker. “It was time I didn’t have,” he said.

Dr. Pausch said that his wife persuaded him to write the book, but that he was worried it would take too much time away from the children. Because he rode his bike every day to keep up his strength, he spoke with his co-writer, Mr. Zaslow, by phone on 53 one-hour bike rides.

The real wisdom of Dr. Pausch is that he tries to enjoy every day he has left with his family, while at the same time trying to prepare them for life without him. To that end, he is videotaping himself spending time with Dylan, Logan and Chloe so they can look back and see how he felt about them.