Hybrid Theory entered the world at a very particular moment. It was Linkin Park’s first album, but even its title carried the band’s past, because Hybrid Theory had originally been the first name of the group before they became Linkin Park and used the old name as the album title. The record became the best selling album in America for 2001, with nearly 5 million copies in the United States and around 14 million worldwide. And yet even those enormous numbers are considered by some to be smaller than they might have been.