"Hybrid Theory" is the debut studio album by the American rock band Linkin Park, released in 2000. The album blends various musical styles, including nu-metal, rap-rock, and alternative rock, which helped define the sound of the early 2000s. It features hit singles like "In the End" and "Crawling," showcasing the band's unique combination of heavy guitar riffs and melodic vocals. The album received critical acclaim and commercial success, selling over 10 million copies in the United States alone. It is often regarded as one of the most influential albums of its time, paving the way for a new generation of rock music that incorporated elements of hip-hop and electronic music.