ONE AFTERNOON IN THE EARLY 1980S, the sales staff and agents of Genius Group, a mishmash of trendy Italian clothing labels, were previewing the upcoming collections and discussing strategy. When talk turned to their second-string, $7 million jeans company Diesel, a production manager with a minority stake and an unfashionable mustache upbraided the others, "Guys, take this seriously because one day we're going to be bigger than Levi's."
"We all laughed and said, 'this guy is crazy,'" remembers former Genius president Adriano Goldschmied, who was running the meeting that day. "Diesel was a brand we had created to get rid of...