Given the popularity of the INC. 100, we were hardly surprised at the response three years ago when we published an indepth study of the founders of the companies on the list ("Who's Running America's Fastest-Growing Companies," August 1983, page 41). Since then, we've been deluged with calls and letters from readers wondering when we would do a similar study of the INC. 500, focusing on the founders of America's privately held growth companies. Wonder no more. Next month, INC. will publish a detailed portrait of the founders and leaders of the INC. 500. The report will challenge more than a few myths about the people who are building some of this country's leading private companies.