Twenty years after the memoir about his life was published, Morrie Schwartz is still teaching lessons about life, love, forgiveness and generosity.

That, says author and Free Press columnist Mitch Albom, is more than he ever hoped for "Tuesdays with Morrie," the book he wrote about lessons learned from weekly visits with Schwartz, his favorite college professor and mentor, in the months leading up to his death in 1995 of ALS, a progressive neurodegenerative disease.

On Sunday, when he appeared on Oprah Winfrey’s show, "SuperSoul Sunday," on OWN, Albom talked about how those lessons still resonate.

"I’m happy that Morrie still gets to teach," Albom said. "For someone who’s not even here to have that kind of influence 20 years later, I think every teacher dreams about having that kind of effect. And (Oprah) helped bring that to the world."

It was Winfrey’s 1997 television endorsement, Albom said, that made his "tiny book. … most of the publishers we went to weren’t interested" and helped turn it into an international best-seller.

"I don’t even know how Oprah Winfrey found out about it," he said. "But she found it, and after I did the show, I remember the president of her company called my publisher and said, ‘I don’t know how many books you have out there, but you should probably print up some more.’

"As soon as the show aired, the country was sold out; you couldn’t get them anywhere in America for like three weeks until they reprinted them again.

"I always was grateful to her for finding ‘Tuesdays with Morrie’ when nobody else had really known it was out."

The "SuperSoul Sunday" episode featuring Albom was filmed at Winfrey’s Santa Barbara, Calif., home.

He was impressed with her interview skills 20 years ago, and was equally impressed at this meeting, noting that Winfrey had the latest edition of his book which includes Albom’s reflections two decades after Schwartz’s death.

"She asked me what did I mean by this, and what did I mean by that," he said. "She’s still the same after all these years and despite all her success. She takes every book very seriously, and every interview very seriously. We were very comfortable seeing each other.

"She asked me a lot about the lessons that still resonate from the time that I spent with Morrie. The ones that resonate with her and the ones that resonate with me as we’ve both gotten older, and which ones have been easier to live up to than others and the impact that the book has had around the world, what I’ve seen and where I’ve gone and what I’ve put into action, and how it’s changed me, how it’s changed the trajectory of my life."

Albom said Winfrey was curious about his work in Haiti, where he operates the Have Faith Haiti Orphanage/Mission in Port-au-Prince, and about his time withMedjerda (Chika) Jeune, a little girl from the orphanage who had incurable brain cancer and came to live with Albom and his wife, Janine. Chika became part of their family; she died in April.

"She knew about that, and she asked me about what that was like," he said, noting that that his experiences with Schwartz and his time with Chika had some parallels.

"It was almost to the month 20 years earlier, I found out Morrie had ALS and 20 years later, I found out Chika had a brain tumor," he said. "And in both cases, my life changed dramatically once I heard that news.

"You know, in Morrie’s case, I started to go and visit him, and everything that led to. In Chika’s case, I brought her to America, thinking we’d be able to take care of it and she’d be back in Haiti in a month or two. But she never left; she never went home, She was here for two years."

The hourlong show, he said, affords him the chance to talk depth about the lessons he learned from Schwartz and how his time with Chika also touched his life.

"‘SuperSoul Sunday’ is a thinking show; it’s a philosophical show," he said. Winfrey "talks about things that resonate for other people. It’s not an interview. It’s not about like, ‘Tell us about what it’s like to be an author.’ It’s not about that at all."

Rather, he said, Winfrey explores deeper questions about issues like forgiveness, and why Schwartz’s mantra — forgive everybody everything — is one she’s come to embrace over the years.

"I’ve had a lot of people say to me, ‘Oh, I saw you on Oprah, talking about ‘Tuesdays with Morrie.’ Well, to all the people who’ve said that to me over the years, here’s the second part of that conversation. It’s 20 years later, and we’ve finished talking about it. Hopefully, they’ll enjoy it. I felt very honored that she had taken the book very seriously 20 years ago and still does."