What are the lessons for product innovation?

Barbie was born in 1959, but she has never aged because it is a doll. To date, more than a billion Barbies have been sold by the US company that owns it, Mattel Corporation, making it their largest and most profi table line.
Mattel is the world’s second-largest toymaker after Lego. Ruth Handler, who founded the company along with her husband, Elliot, modelled the doll on an 11.5-inch plastic German toy called Lilli sold to adult men. She named the adapted doll after her daughter, Barbara. But how has this plastic doll endured for so long in an industry notorious for its susceptibility to fi ckleness and fashion? Surely it must have come to the end of its life-cycle? The answer lies in innovative marketing and product extension.