John Caples, Author Of Famous Ad Line

NEW YORK - John Caples, who as a young copywriter wrote one of advertising's most famous lines - ``They Laughed When I Sat Down at the Piano . . .'' - died yesterday. He was 90 years old.

Caples wrote the famous headline in 1926 for the U.S. School of Music. The entire headline read: ``They Laughed When I Sat Down at the Piano . . . But When I Started to Play!''

The ad was an instant success and spawned dozens of imitations over the years that used ``They Laughed When . . .'' as the introduction.

Caples, who went on to become an expert in direct-response advertising, had worked one year at Ruthrauff & Ryan when he wrote the famous ad.