What is the role of a product manager?

"A product manager develops and implements a complete strategy and marketing program for a specific product or brand of product. Some companies may have numerous brands of the same type of product, such as many versions of laundry soap, each with different target markets, brand names, and attributes. Product management first appeared at Procter & Gamble in 1929. A new company soap, Camay, was not doing well, so a young Procter & Gamble executive was assigned to devote his exclusive attention to developing and promoting this product. He was successful, and the company soon added other product managers. Since then, many firms, especially consumer products companies, have set up product management organizations."