GUEST: It was actually my grandmother's guitar.

She bought it from her brother right before he left for World War II.

With intentions of, uh, selling it back to him when he arrived back home, but a few things changed.

Uh, she kept the guitar, uh, passed it down to my father, and my father recently, uh, passed it to me.

APPRAISER: At some point in time, somebody played this guitar a lot; do you know who did that?

GUEST: Uh, it was probably a combination of my grandmother and my father.

APPRAISER: Well, there's a good reason that they played it, because this is a great guitar.

This is a Martin-- the serial number dates it as a 1937.

This guitar comes from what they call the golden era of guitar making at the Martin guitar company, which at that time was in Nazareth, Pennsylvania, and still is in Nazareth, Pennsylvania.

Consistently, when you find a guitar from that period, they're built beautifully and they sound great.

The top is made of Adirondack spruce.

Later on, Martin switched to Sitka spruce, and that really adds to the interest and intrigue of this guitar.

The fingerboard is ebony, the back and sides and the neck are mahogany.

The bridge is ebony.

GUEST: Okay.

APPRAISER: What does affect the value on this guitar is that at some point in time somebody either refinished or over-finished the original finish on the top.

It's much more orange than it should be.

And if you look closely, it's not a great job.

It's got a beautiful neck.

It has original tuners, except for one, which is still a pretty old tuner.

It's probably a mid-'40s tuner.

All in all, a 1937 Martin from this era is considered one of the most desirable guitars for bluegrass, folk musicians.

So this is a great thing.

And I had the opportunity to tune it up before we came on, and I was... one of the reasons people like this guitar is that when you play it... (strums chord) ...it just sounds great.

(strums chord) (strumming) That's a world-class sound.

GUEST: Right.

APPRAISER: It's a beautiful guitar.

Condition does affect the value.

I think in a retail environment this guitar would sell for somewhere between $15,000 and $18,000.

GUEST: Wow... (chuckling).

Wow.

Nice.

APPRAISER: If this guitar had nothing done to it, it would be worth approximately $35,000.