GUEST: It's one of several baseballs we have that Thurm signed.

He was a family friend.

We have lots of memorabilia of his.

It's all personal, since we did know him so well.

He wasn't a huge sports figure in our eyes.

He was a friend.

Thurm was in partnership on a particular development, which then my dad dedicated the street to him.

So there, there's a Munson Street in Canton, Ohio.

APPRAISER: And, of course, the tragedy of his death is an unforgettable moment in, uh, in many, many people's lives.

I was, I was just a young kid in '79 when Thurman Munson was tragically killed in a small plane crash.

But that's one of my earliest memories, is, uh, hearing that on the news.

GUEST: Yeah.

APPRAISER: And, uh, being, being shocked by it.

But he continues to be an inspiration today and one of the most difficult signatures to get.

Thurman did not like signing autographs for most people.

GUEST: No, he didn't.

Except for my father.

APPRAISER: Well, he liked doing that, right, well, I mean, that, we're very fortunate for that.

Even in his biography, he talks about he'd much rather shake somebody's hand.

GUEST: Right.

APPRAISER: If it was a kid, it was a different story; he would sign.

Thurman Munson is considered one of the most important autographs, certainly of the last 50 years when it comes to baseball memorabilia.

Very, very rarely on a baseball by itself.

GUEST: I didn't know that.

APPRAISER: Yeah.

And, and what's amazing about this ball in particular, it is not an official American League ball.

It's basically a ball you'd get at a sports store in the '70s.

And he signed it beautifully, and then it was obviously put back in the box...

GUEST: Mm-hmm.

APPRAISER: ...and nobody's touched it...

GUEST: No.

APPRAISER: ...since; it's pristine.

Today, people grade baseballs because of the boldness of the signature and the, the whiteness of the ball and things like that, the condition.

This is pretty flawless.

You have the personal connection; you have, of course, the memories of the man himself.

But this baseball, in and of itself, is a treasure.

The Yankee fandom?

I mean, you don't get much bigger than that when it comes to collectible baseballs and things.

GUEST: Right.

APPRAISER: If this was in an auction today, I think it could sell somewhere in the $20,000 to $30,000 range.

Just this one.

GUEST: Oh, my.

That's unexpected.

Hmm.

He was larger than life, and he loved his family and he loved his community.

And we loved him.

APPRAISER: I'd insure it for $40,000 to $50,000, somewhere in that range.