(FORTUNE Magazine) – The next time you attend a social dinner, do not, whatever you do, whip out your business card and hand it across the table. ''That is so crass and so bad,'' admonishes Letitia Baldrige, 62, author of the Complete Guide to Executive Manners, and Jacqueline Kennedy's White House social secretary. ''You don't solicit business in someone's home.'' Yikes. According to Baldrige, there is an epidemic of bad manners in the workplace: Executives should be spending less time minding their P&Ls and more time minding their P's and Q's. But not to worry. Together with professional hostess Marjorie (Entertaining All Year Round) Reed and marketing consultant Camille Lavington, Baldrige is holding a seminar March 19 in New York City called ''The Profile of a Business Winner.'' It's a crash course in executive manners -- and it's not just for baby-boomers. ''The young need it and know they need it,'' she says. ''CEOs need it but don't know it.'' If enough boors show up, the trio plans to take its show on the road. For $400, attendees will learn how to survive a faux pas (such as the time Baldrige introduced a Congressman's wife to President Kennedy by the name of the man's mistress); the art of self-promotion; and the secrets to successful, cost-efficient business entertaining. ''Yuppies are going at a breakneck pace, and there is no one to explain to them the social amenities,'' says Reed, the doyenne of the dinner party circuit. ''Entertaining is a gift of love.'' And all this time, you thought you were doing it for money.