GUEST: I inherited it about 14 years ago from a cousin who had been in the Women's Army Corps during World War II.

And she went to Paris and she bought this painting.

She is a cat lover, and she paid a few hundred dollars for it, and she was told that it was extremely valuable.

APPRAISER: And this was in the 1940s?

GUEST: Yes, mm-hmm.

APPRAISER: Okay.

GUEST: And I'm not a cat lover.

(laughs) So it's been on my porch for 15 years.

APPRAISER: And what do you know about it?

GUEST: I know that he was a contemporary of Toulouse-Lautrec, that he was Swiss and he came to Paris in 1881, and he is more noted for his posters.

APPRAISER: The artist's name is Theophile Steinlen.

And you're absolutely right, he was a contemporary and a friend of Toulouse-Lautrec's, also a famous poster artist.

He was born in Switzerland, and, in his early 20s, he moved to Paris.

And he's working in Paris in the 1880s as an illustrator, and soon after that, as a poster artist.

He did a number of images of workers and very much had a social agenda in imaging poorer people, downtrodden people.

But what he's best known for are his posters of Parisian nightclubs and theater programs, and, of course, the beloved cats.

And most of his models are his own cats.

GUEST: Oh.

APPRAISER: So he, he didn't have to go far...

GUEST: I see.

APPRAISER: ...to find cats to draw.

GUEST: Mm-hmm.

APPRAISER: Now, you said you thought it was a painting initially.

GUEST: Yeah.

APPRAISER: It's actually a color lithograph.

GUEST: Oh.

APPRAISER: So it's a multiple, it's a print.

He made this in an edition of several hundred in 1909.

And it's actually a companion piece to another cat, which is an inside cat, known as the winter cat.

You have the summer cat.

GUEST: Oh, okay.

APPRAISER: He's signed it in pencil right below the cat's front paws.

Up here is his monogram.

And then right here you can see a blind stamp...

GUEST: Oh, yes.

APPRAISER: ...in the wood.

GUEST: Oh!

APPRAISER: That's the publisher of this print, whose name was Sagot, and it's actually turned on its side.

It's "Sagot, Paris," and he worked with the publisher Sagot throughout his career in Paris to issue these prints.

You have one that's in very, very good condition.

Framewise, it's not good to have a print pushed up to a piece of glass like this.

It would be much better off to have it taken out of this frame and put in a mat so the print itself isn't directly touching the glass.

GUEST: I see.

APPRAISER: What you get here are some humidification marks.

This faint, faint, light mark in the wood, that's caused by the print, over time, pressing up to the glass.

GUEST: Oh.

APPRAISER: In this condition, if I had to put a replacement value or a retail value on this...

GUEST: Mm-hmm.

APPRAISER: ...I would say it's around $10,000 to $12,000.

GUEST: (exhales) APPRAISER: So you're at the top end of the Steinlen cat print market.

GUEST: I'm stunned.

I'm stunned.

(laughing) APPRAISER: Do you like cats any more after that?

(both laughing) GUEST: I'm beginning to love it.

APPRAISER: Great.

GUEST: I just can't believe it-- I can't believe it.

(both laughing)