The music of "Hybrid Theory" draws from diverse inspirations. Bennington's singing style is influenced by acts such as Depeche Mode and Stone Temple Pilots, while the riffs and playing techniques of guitarist Brad Delson are modeled after Deftones, Guns N' Roses, U2, and The Smiths. The lyrical content of the songs primarily touches upon the problems that Bennington encountered during his childhood, including constant and excessive drug and alcohol abuse, the divorce of his parents, isolation, disappointments, and the aftermath feelings of failed relationships. Stylistically, the album has been described as nu metal, rap metal, rap rock, alternative metal, alternative rock, and hard rock.